diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5e7fb0f..212c829 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,13 @@ this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+## [0.11.0] - 2025-06-06
+
+### Added
+
+- Support for transactions, a big thanks to `@lukwam` for this! For more details of how
+  to use this, see the new section in the README.
+
 ## [0.10.0] - 2025-02-26
 
 ### Added
@@ -283,7 +290,8 @@ this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Update README.md
 - Update .gitignore
 
-[unreleased]: https://github.com/ioxiocom/firedantic/compare/0.10.0...HEAD
+[unreleased]: https://github.com/ioxiocom/firedantic/compare/0.11.0...HEAD
+[0.11.0]: https://github.com/ioxiocom/firedantic/compare/0.10.0...0.11.0
 [0.10.0]: https://github.com/ioxiocom/firedantic/compare/0.9.0...0.10.0
 [0.9.0]: https://github.com/ioxiocom/firedantic/compare/0.8.1...0.9.0
 [0.8.1]: https://github.com/ioxiocom/firedantic/compare/0.8.0...0.8.1
diff --git a/README.md b/README.md
index feda0fd..e80d025 100644
--- a/README.md
+++ b/README.md
@@ -320,6 +320,157 @@ if __name__ == "__main__":
     asyncio.run(main())
 ```
 
+## Transactions
+
+Firedantic has basic support for
+[Firestore Transactions](https://firebase.google.com/docs/firestore/manage-data/transactions).
+The following methods can be used in a transaction:
+
+- `Model.delete(transaction=transaction)`
+- `Model.find_one(transaction=transaction)`
+- `Model.find(transaction=transaction)`
+- `Model.get_by_doc_id(transaction=transaction)`
+- `Model.get_by_id(transaction=transaction)`
+- `Model.reload(transaction=transaction)`
+- `Model.save(transaction=transaction)`
+- `SubModel.get_by_id(transaction=transaction)`
+
+When using transactions, note that read operations must come before write operations.
+
+### Transaction examples
+
+In this example (async and sync version of it below), we are updating a `City` to
+increment and decrement the population of it, both using an instance method and a
+standalone function. Please note that the `@async_transactional` and `@transactional`
+decorators always expect the first argument of the wrapped function to be `transaction`;
+i.e. you can not directly wrap an instance method that has `self` as the first argument
+or a class method that has `cls` as the first argument.
+
+#### Transaction example (async)
+
+```python
+import asyncio
+from os import environ
+from unittest.mock import Mock
+
+import google.auth.credentials
+from google.cloud.firestore import AsyncClient
+from google.cloud.firestore_v1 import async_transactional, AsyncTransaction
+
+from firedantic import AsyncModel, configure, get_async_transaction
+
+# Firestore emulator must be running if using locally.
+if environ.get("FIRESTORE_EMULATOR_HOST"):
+    client = AsyncClient(
+        project="firedantic-test",
+        credentials=Mock(spec=google.auth.credentials.Credentials),
+    )
+else:
+    client = AsyncClient()
+
+configure(client, prefix="firedantic-test-")
+
+
+class City(AsyncModel):
+    __collection__ = "cities"
+    population: int
+
+    async def increment_population(self, increment: int = 1):
+        @async_transactional
+        async def _increment_population(transaction: AsyncTransaction) -> None:
+            await self.reload(transaction=transaction)
+            self.population += increment
+            await self.save(transaction=transaction)
+
+        t = get_async_transaction()
+        await _increment_population(transaction=t)
+
+
+async def main():
+    @async_transactional
+    async def decrement_population(
+        transaction: AsyncTransaction, city: City, decrement: int = 1
+    ):
+        await city.reload(transaction=transaction)
+        city.population = max(0, city.population - decrement)
+        await city.save(transaction=transaction)
+
+    c = City(id="SF", population=1)
+    await c.save()
+    await c.increment_population(increment=1)
+    assert c.population == 2
+
+    t = get_async_transaction()
+    await decrement_population(transaction=t, city=c, decrement=5)
+    assert c.population == 0
+
+
+if __name__ == "__main__":
+    asyncio.run(main())
+```
+
+#### Transaction example (sync)
+
+```python
+from os import environ
+from unittest.mock import Mock
+
+import google.auth.credentials
+from google.cloud.firestore import Client
+from google.cloud.firestore_v1 import transactional, Transaction
+
+from firedantic import Model, configure, get_transaction
+
+# Firestore emulator must be running if using locally.
+if environ.get("FIRESTORE_EMULATOR_HOST"):
+    client = Client(
+        project="firedantic-test",
+        credentials=Mock(spec=google.auth.credentials.Credentials),
+    )
+else:
+    client = Client()
+
+configure(client, prefix="firedantic-test-")
+
+
+class City(Model):
+    __collection__ = "cities"
+    population: int
+
+    def increment_population(self, increment: int = 1):
+        @transactional
+        def _increment_population(transaction: Transaction) -> None:
+            self.reload(transaction=transaction)
+            self.population += increment
+            self.save(transaction=transaction)
+
+        t = get_transaction()
+        _increment_population(transaction=t)
+
+
+def main():
+    @transactional
+    def decrement_population(
+        transaction: Transaction, city: City, decrement: int = 1
+    ):
+        city.reload(transaction=transaction)
+        city.population = max(0, city.population - decrement)
+        city.save(transaction=transaction)
+
+    c = City(id="SF", population=1)
+    c.save()
+    c.increment_population(increment=1)
+    assert c.population == 2
+
+    t = get_transaction()
+    decrement_population(transaction=t, city=c, decrement=5)
+    assert c.population == 0
+
+
+if __name__ == "__main__":
+    main()
+```
+
 ## Development
 
 PRs are welcome!
diff --git a/firedantic/__init__.py b/firedantic/__init__.py
index 7b0e16b..e4f79d2 100644
--- a/firedantic/__init__.py
+++ b/firedantic/__init__.py
@@ -32,6 +32,11 @@
 )
 from firedantic._sync.ttl_policy import set_up_ttl_policies
 from firedantic.common import collection_group_index, collection_index
-from firedantic.configurations import CONFIGURATIONS, configure
+from firedantic.configurations import (
+    CONFIGURATIONS,
+    configure,
+    get_async_transaction,
+    get_transaction,
+)
 from firedantic.exceptions import *
 from firedantic.utils import get_all_subclasses
diff --git a/firedantic/_async/helpers.py b/firedantic/_async/helpers.py
index 10bd5ef..c77b650 100644
--- a/firedantic/_async/helpers.py
+++ b/firedantic/_async/helpers.py
@@ -4,7 +4,8 @@
 async def truncate_collection(
     col_ref: AsyncCollectionReference, batch_size: int = 128
 ) -> int:
-    """Removes all documents inside a collection.
+    """
+    Removes all documents inside a collection.
 
     :param col_ref: A collection reference to the collection to be truncated.
     :param batch_size: Batch size for listing documents.
diff --git a/firedantic/_async/model.py b/firedantic/_async/model.py
index 9c6af1c..84251df 100644
--- a/firedantic/_async/model.py
+++ b/firedantic/_async/model.py
@@ -10,6 +10,7 @@
     FieldFilter,
 )
 from google.cloud.firestore_v1.async_query import AsyncQuery
+from google.cloud.firestore_v1.async_transaction import AsyncTransaction
 
 import firedantic.operators as op
 from firedantic import async_truncate_collection
@@ -41,6 +42,11 @@
 
 
 def get_collection_name(cls, name: Optional[str]) -> str:
+    """
+    Returns the collection name.
+
+    :raise CollectionNotDefined: If the collection name is not defined.
+    """
     if not name:
         raise CollectionNotDefined(f"Missing collection name for {cls.__name__}")
 
@@ -55,7 +61,8 @@ def _get_col_ref(cls, name: Optional[str]) -> AsyncCollectionReference:
 
 
 class AsyncBareModel(pydantic.BaseModel, ABC):
-    """Base model class.
+    """
+    Base model class.
 
     Implements basic functionality for Pydantic models, such as save, delete, find etc.
     """
@@ -66,13 +73,18 @@ class AsyncBareModel(pydantic.BaseModel, ABC):
     __composite_indexes__: Optional[Iterable[IndexDefinition]] = None
 
     async def save(
-        self, *, exclude_unset: bool = False, exclude_none: bool = False
+        self,
+        *,
+        exclude_unset: bool = False,
+        exclude_none: bool = False,
+        transaction: Optional[AsyncTransaction] = None,
     ) -> None:
         """
         Saves this model in the database.
 
         :param exclude_unset: Whether to exclude fields that have not been explicitly set.
         :param exclude_none: Whether to exclude fields that have a value of `None`.
+        :param transaction: Optional transaction to use.
         :raise DocumentIDError: If the document ID is not valid.
         """
         data = self.model_dump(
@@ -82,28 +94,35 @@ async def save(
             del data[self.__document_id__]
 
         doc_ref = self._get_doc_ref()
-        await doc_ref.set(data)
+        if transaction is not None:
+            transaction.set(doc_ref, data)
+        else:
+            await doc_ref.set(data)
         setattr(self, self.__document_id__, doc_ref.id)
 
-    async def delete(self) -> None:
+    async def delete(self, transaction: Optional[AsyncTransaction] = None) -> None:
         """
         Deletes this model from the database.
 
         :raise DocumentIDError: If the ID is not valid.
         """
-        await self._get_doc_ref().delete()
+        if transaction is not None:
+            transaction.delete(self._get_doc_ref())
+        else:
+            await self._get_doc_ref().delete()
 
-    async def reload(self) -> None:
+    async def reload(self, transaction: Optional[AsyncTransaction] = None) -> None:
         """
         Reloads this model from the database.
 
+        :param transaction: Optional transaction to use.
         :raise ModelNotFoundError: If the document ID is missing in the model.
         """
         doc_id = self.__dict__.get(self.__document_id__)
         if doc_id is None:
             raise ModelNotFoundError("Can not reload unsaved model")
 
-        updated_model = await self.get_by_doc_id(doc_id)
+        updated_model = await self.get_by_doc_id(doc_id, transaction=transaction)
         updated_model_doc_id = updated_model.__dict__[self.__document_id__]
         assert doc_id == updated_model_doc_id
 
@@ -111,7 +130,7 @@ async def reload(self) -> None:
 
     def get_document_id(self):
         """
-        Get the document ID for this model instance
+        Returns the document ID for this model instance.
 
         :raise DocumentIDError: If the ID is not valid.
         """
@@ -123,14 +142,17 @@ def get_document_id(self):
     _OrderBy = List[Tuple[str, OrderDirection]]
 
     @classmethod
-    async def find(
+    async def find(  # pylint: disable=too-many-arguments
         cls: Type[TAsyncBareModel],
         filter_: Optional[Dict[str, Union[str, dict]]] = None,
         order_by: Optional[_OrderBy] = None,
         limit: Optional[int] = None,
         offset: Optional[int] = None,
+        transaction: Optional[AsyncTransaction] = None,
     ) -> List[TAsyncBareModel]:
-        """Returns a list of models from the database based on a filter.
+        """
+        Returns a list of models from the database based on a filter.
+
         The list can be sorted with the order_by parameter, limits and offets can also be applied.
 
         Example: `Company.find({"company_id": "1234567-8"})`.
@@ -142,6 +164,7 @@ async def find(
         :param order_by: List of columns and direction to order results by.
         :param limit: Maximum results to return.
         :param offset: Skip the first n results.
+        :param transaction: Optional transaction to use.
         :return: List of found models.
         """
         query: Union[AsyncQuery, AsyncCollectionReference] = cls._get_col_ref()
@@ -175,7 +198,7 @@ def _cls(doc_id: str, data: Dict[str, Any]) -> TAsyncBareModel:
         return [
             _cls(doc_id, doc_dict)
             async for doc_id, doc_dict in (
-                (doc.id, doc.to_dict()) async for doc in query.stream()  # type: ignore
+                (doc.id, doc.to_dict()) async for doc in query.stream(transaction=transaction)  # type: ignore
             )
             if doc_dict is not None
         ]
@@ -184,7 +207,7 @@ def _cls(doc_id: str, data: Dict[str, Any]) -> TAsyncBareModel:
     def _add_filter(
         cls, query: Union[AsyncQuery, AsyncCollectionReference], field: str, value: Any
     ) -> Union[AsyncQuery, AsyncCollectionReference]:
-        if type(value) is dict:
+        if isinstance(value, dict):
             for f_type in value:
                 if f_type not in FIND_TYPES:
                     raise ValueError(
@@ -203,32 +226,42 @@ async def find_one(
         cls: Type[TAsyncBareModel],
         filter_: Optional[Dict[str, Union[str, dict]]] = None,
         order_by: Optional[_OrderBy] = None,
+        transaction: Optional[AsyncTransaction] = None,
     ) -> TAsyncBareModel:
-        """Returns one model from the DB based on a filter.
+        """
+        Returns one model from the DB based on a filter.
 
         :param filter_: The filter criteria.
         :param order_by: List of columns and direction to order results by.
         :return: The model instance.
         :raise ModelNotFoundError: If the entry is not found.
         """
-        model = await cls.find(filter_, limit=1, order_by=order_by)
+        model = await cls.find(
+            filter_, limit=1, order_by=order_by, transaction=transaction
+        )
         try:
             return model[0]
-        except IndexError:
-            raise ModelNotFoundError(f"No '{cls.__name__}' found")
+        except IndexError as e:
+            raise ModelNotFoundError(f"No '{cls.__name__}' found") from e
 
     @classmethod
-    async def get_by_doc_id(cls: Type[TAsyncBareModel], doc_id: str) -> TAsyncBareModel:
-        """Returns a model based on the document ID.
+    async def get_by_doc_id(
+        cls: Type[TAsyncBareModel],
+        doc_id: str,
+        transaction: Optional[AsyncTransaction] = None,
+    ) -> TAsyncBareModel:
+        """
+        Returns a model based on the document ID.
 
         :param doc_id: The document ID of the entry.
+        :param transaction: Optional transaction to use.
         :return: The model.
         :raise ModelNotFoundError: Raised if no matching document is found.
         """
 
         try:
             cls._validate_document_id(doc_id)
-        except InvalidDocumentID:
+        except InvalidDocumentID as e:
             # Getting a document with doc_id set to an empty string would raise a
             # google.api_core.exceptions.InvalidArgument exception and a doc_id
             # containing an uneven number of slashes would raise a
@@ -236,10 +269,10 @@ async def get_by_doc_id(cls: Type[TAsyncBareModel], doc_id: str) -> TAsyncBareMo
             # could even load data from a sub collection instead of the desired one.
             raise ModelNotFoundError(
                 f"No '{cls.__name__}' found with {cls.__document_id__} '{doc_id}'"
-            )
+            ) from e
 
         document: DocumentSnapshot = (
-            await cls._get_col_ref().document(doc_id).get()
+            await cls._get_col_ref().document(doc_id).get(transaction=transaction)
         )  # type: ignore
         data = document.to_dict()
         if data is None:
@@ -253,7 +286,8 @@ async def get_by_doc_id(cls: Type[TAsyncBareModel], doc_id: str) -> TAsyncBareMo
 
     @classmethod
     async def truncate_collection(cls, batch_size: int = 128) -> int:
-        """Removes all documents inside a collection.
+        """
+        Removes all documents inside a collection.
 
         :param batch_size: Batch size for listing documents.
         :return: Number of removed documents.
@@ -265,11 +299,16 @@ async def truncate_collection(cls, batch_size: int = 128) -> int:
 
     @classmethod
     def _get_col_ref(cls) -> AsyncCollectionReference:
-        """Returns the collection reference."""
+        """
+        Returns the collection reference.
+        """
         return _get_col_ref(cls, cls.__collection__)
 
     @classmethod
     def get_collection_name(cls) -> str:
+        """
+        Returns the collection name.
+        """
         return get_collection_name(cls, cls.__collection__)
 
     def _get_doc_ref(self) -> AsyncDocumentReference:
@@ -319,8 +358,19 @@ class AsyncModel(AsyncBareModel):
     id: Optional[str] = None
 
     @classmethod
-    async def get_by_id(cls: Type[TAsyncBareModel], id_: str) -> TAsyncBareModel:
-        return await cls.get_by_doc_id(id_)
+    async def get_by_id(
+        cls: Type[TAsyncBareModel],
+        id_: str,
+        transaction: Optional[AsyncTransaction] = None,
+    ) -> TAsyncBareModel:
+        """
+        Get single model by document ID.
+
+        :param id_: Document ID.
+        :param transaction: Optional transaction to use.
+        :raises ModelNotFoundError: If no model was found by given id.
+        """
+        return await cls.get_by_doc_id(id_, transaction=transaction)
 
 
 class AsyncBareSubCollection(ABC):
@@ -329,6 +379,9 @@ class AsyncBareSubCollection(ABC):
 
     @classmethod
     def model_for(cls, parent, model_class):
+        """
+        Returns the model for this subcollection.
+        """
         parent_props = parent.model_dump(by_alias=True)
 
         name = model_class.__name__
@@ -356,7 +409,9 @@ def _create(cls: Type[TAsyncBareSubModel], **kwargs) -> TAsyncBareSubModel:
 
     @classmethod
     def _get_col_ref(cls) -> AsyncCollectionReference:
-        """Returns the collection reference."""
+        """
+        Returns the collection reference.
+        """
         if cls.__collection__ is None or "{" in cls.__collection__:
             raise CollectionNotDefined(
                 f"{cls.__name__} is not properly prepared. "
@@ -366,6 +421,9 @@ def _get_col_ref(cls) -> AsyncCollectionReference:
 
     @classmethod
     def model_for(cls, parent):
+        """
+        Returns the model for this submodel.
+        """
         return cls.Collection.model_for(parent, cls)
 
 
@@ -373,12 +431,19 @@ class AsyncSubModel(AsyncBareSubModel):
     id: Optional[str] = None
 
     @classmethod
-    async def get_by_id(cls: Type[TAsyncBareModel], id_: str) -> TAsyncBareModel:
+    async def get_by_id(
+        cls: Type[TAsyncBareModel],
+        id_: str,
+        transaction: Optional[AsyncTransaction] = None,
+    ) -> TAsyncBareModel:
         """
         Get single item by document ID
+
+        :param id_: Document ID.
+        :param transaction: Optional transaction to use.
         :raises ModelNotFoundError:
         """
-        return await cls.get_by_doc_id(id_)
+        return await cls.get_by_doc_id(id_, transaction=transaction)
 
 
 class AsyncSubCollection(AsyncBareSubCollection, ABC):
diff --git a/firedantic/_sync/helpers.py b/firedantic/_sync/helpers.py
index 3feb0d5..57dfe99 100644
--- a/firedantic/_sync/helpers.py
+++ b/firedantic/_sync/helpers.py
@@ -2,7 +2,8 @@
 
 
 def truncate_collection(col_ref: CollectionReference, batch_size: int = 128) -> int:
-    """Removes all documents inside a collection.
+    """
+    Removes all documents inside a collection.
 
     :param col_ref: A collection reference to the collection to be truncated.
     :param batch_size: Batch size for listing documents.
diff --git a/firedantic/_sync/model.py b/firedantic/_sync/model.py
index 4fa7d6d..78ec372 100644
--- a/firedantic/_sync/model.py
+++ b/firedantic/_sync/model.py
@@ -10,6 +10,7 @@
     FieldFilter,
 )
 from google.cloud.firestore_v1.base_query import BaseQuery
+from google.cloud.firestore_v1.transaction import Transaction
 
 import firedantic.operators as op
 from firedantic import truncate_collection
@@ -41,6 +42,11 @@
 
 
 def get_collection_name(cls, name: Optional[str]) -> str:
+    """
+    Returns the collection name.
+
+    :raise CollectionNotDefined: If the collection name is not defined.
+    """
     if not name:
         raise CollectionNotDefined(f"Missing collection name for {cls.__name__}")
 
@@ -55,7 +61,8 @@ def _get_col_ref(cls, name: Optional[str]) -> CollectionReference:
 
 
 class BareModel(pydantic.BaseModel, ABC):
-    """Base model class.
+    """
+    Base model class.
 
     Implements basic functionality for Pydantic models, such as save, delete, find etc.
     """
@@ -65,12 +72,19 @@ class BareModel(pydantic.BaseModel, ABC):
     __ttl_field__: Optional[str] = None
     __composite_indexes__: Optional[Iterable[IndexDefinition]] = None
 
-    def save(self, *, exclude_unset: bool = False, exclude_none: bool = False) -> None:
+    def save(
+        self,
+        *,
+        exclude_unset: bool = False,
+        exclude_none: bool = False,
+        transaction: Optional[Transaction] = None,
+    ) -> None:
         """
         Saves this model in the database.
 
         :param exclude_unset: Whether to exclude fields that have not been explicitly set.
         :param exclude_none: Whether to exclude fields that have a value of `None`.
+        :param transaction: Optional transaction to use.
         :raise DocumentIDError: If the document ID is not valid.
         """
         data = self.model_dump(
@@ -80,28 +94,35 @@ def save(self, *, exclude_unset: bool = False, exclude_none: bool = False) -> No
             del data[self.__document_id__]
 
         doc_ref = self._get_doc_ref()
-        doc_ref.set(data)
+        if transaction is not None:
+            transaction.set(doc_ref, data)
+        else:
+            doc_ref.set(data)
         setattr(self, self.__document_id__, doc_ref.id)
 
-    def delete(self) -> None:
+    def delete(self, transaction: Optional[Transaction] = None) -> None:
         """
         Deletes this model from the database.
 
         :raise DocumentIDError: If the ID is not valid.
         """
-        self._get_doc_ref().delete()
+        if transaction is not None:
+            transaction.delete(self._get_doc_ref())
+        else:
+            self._get_doc_ref().delete()
 
-    def reload(self) -> None:
+    def reload(self, transaction: Optional[Transaction] = None) -> None:
         """
         Reloads this model from the database.
 
+        :param transaction: Optional transaction to use.
         :raise ModelNotFoundError: If the document ID is missing in the model.
         """
         doc_id = self.__dict__.get(self.__document_id__)
         if doc_id is None:
             raise ModelNotFoundError("Can not reload unsaved model")
 
-        updated_model = self.get_by_doc_id(doc_id)
+        updated_model = self.get_by_doc_id(doc_id, transaction=transaction)
         updated_model_doc_id = updated_model.__dict__[self.__document_id__]
         assert doc_id == updated_model_doc_id
 
@@ -109,7 +130,7 @@ def reload(self) -> None:
 
     def get_document_id(self):
         """
-        Get the document ID for this model instance
+        Returns the document ID for this model instance.
 
         :raise DocumentIDError: If the ID is not valid.
         """
@@ -121,14 +142,17 @@ def get_document_id(self):
     _OrderBy = List[Tuple[str, OrderDirection]]
 
     @classmethod
-    def find(
+    def find(  # pylint: disable=too-many-arguments
         cls: Type[TBareModel],
         filter_: Optional[Dict[str, Union[str, dict]]] = None,
         order_by: Optional[_OrderBy] = None,
         limit: Optional[int] = None,
         offset: Optional[int] = None,
+        transaction: Optional[Transaction] = None,
     ) -> List[TBareModel]:
-        """Returns a list of models from the database based on a filter.
+        """
+        Returns a list of models from the database based on a filter.
+
         The list can be sorted with the order_by parameter, limits and offets can also be applied.
 
         Example: `Company.find({"company_id": "1234567-8"})`.
@@ -140,6 +164,7 @@ def find(
         :param order_by: List of columns and direction to order results by.
         :param limit: Maximum results to return.
         :param offset: Skip the first n results.
+        :param transaction: Optional transaction to use.
         :return: List of found models.
         """
         query: Union[BaseQuery, CollectionReference] = cls._get_col_ref()
@@ -173,7 +198,7 @@ def _cls(doc_id: str, data: Dict[str, Any]) -> TBareModel:
         return [
             _cls(doc_id, doc_dict)
             for doc_id, doc_dict in (
-                (doc.id, doc.to_dict()) for doc in query.stream()  # type: ignore
+                (doc.id, doc.to_dict()) for doc in query.stream(transaction=transaction)  # type: ignore
             )
             if doc_dict is not None
         ]
@@ -182,7 +207,7 @@ def _cls(doc_id: str, data: Dict[str, Any]) -> TBareModel:
     def _add_filter(
         cls, query: Union[BaseQuery, CollectionReference], field: str, value: Any
     ) -> Union[BaseQuery, CollectionReference]:
-        if type(value) is dict:
+        if isinstance(value, dict):
             for f_type in value:
                 if f_type not in FIND_TYPES:
                     raise ValueError(
@@ -201,32 +226,40 @@ def find_one(
         cls: Type[TBareModel],
         filter_: Optional[Dict[str, Union[str, dict]]] = None,
         order_by: Optional[_OrderBy] = None,
+        transaction: Optional[Transaction] = None,
     ) -> TBareModel:
-        """Returns one model from the DB based on a filter.
+        """
+        Returns one model from the DB based on a filter.
 
         :param filter_: The filter criteria.
         :param order_by: List of columns and direction to order results by.
         :return: The model instance.
         :raise ModelNotFoundError: If the entry is not found.
         """
-        model = cls.find(filter_, limit=1, order_by=order_by)
+        model = cls.find(filter_, limit=1, order_by=order_by, transaction=transaction)
         try:
             return model[0]
-        except IndexError:
-            raise ModelNotFoundError(f"No '{cls.__name__}' found")
+        except IndexError as e:
+            raise ModelNotFoundError(f"No '{cls.__name__}' found") from e
 
     @classmethod
-    def get_by_doc_id(cls: Type[TBareModel], doc_id: str) -> TBareModel:
-        """Returns a model based on the document ID.
+    def get_by_doc_id(
+        cls: Type[TBareModel],
+        doc_id: str,
+        transaction: Optional[Transaction] = None,
+    ) -> TBareModel:
+        """
+        Returns a model based on the document ID.
 
         :param doc_id: The document ID of the entry.
+        :param transaction: Optional transaction to use.
         :return: The model.
         :raise ModelNotFoundError: Raised if no matching document is found.
         """
 
         try:
             cls._validate_document_id(doc_id)
-        except InvalidDocumentID:
+        except InvalidDocumentID as e:
             # Getting a document with doc_id set to an empty string would raise a
             # google.api_core.exceptions.InvalidArgument exception and a doc_id
             # containing an uneven number of slashes would raise a
@@ -234,10 +267,10 @@ def get_by_doc_id(cls: Type[TBareModel], doc_id: str) -> TBareModel:
             # could even load data from a sub collection instead of the desired one.
             raise ModelNotFoundError(
                 f"No '{cls.__name__}' found with {cls.__document_id__} '{doc_id}'"
-            )
+            ) from e
 
         document: DocumentSnapshot = (
-            cls._get_col_ref().document(doc_id).get()
+            cls._get_col_ref().document(doc_id).get(transaction=transaction)
         )  # type: ignore
         data = document.to_dict()
         if data is None:
@@ -251,7 +284,8 @@ def get_by_doc_id(cls: Type[TBareModel], doc_id: str) -> TBareModel:
 
     @classmethod
     def truncate_collection(cls, batch_size: int = 128) -> int:
-        """Removes all documents inside a collection.
+        """
+        Removes all documents inside a collection.
 
         :param batch_size: Batch size for listing documents.
         :return: Number of removed documents.
@@ -263,11 +297,16 @@ def truncate_collection(cls, batch_size: int = 128) -> int:
 
     @classmethod
     def _get_col_ref(cls) -> CollectionReference:
-        """Returns the collection reference."""
+        """
+        Returns the collection reference.
+        """
         return _get_col_ref(cls, cls.__collection__)
 
     @classmethod
     def get_collection_name(cls) -> str:
+        """
+        Returns the collection name.
+        """
         return get_collection_name(cls, cls.__collection__)
 
     def _get_doc_ref(self) -> DocumentReference:
@@ -317,8 +356,19 @@ class Model(BareModel):
     id: Optional[str] = None
 
     @classmethod
-    def get_by_id(cls: Type[TBareModel], id_: str) -> TBareModel:
-        return cls.get_by_doc_id(id_)
+    def get_by_id(
+        cls: Type[TBareModel],
+        id_: str,
+        transaction: Optional[Transaction] = None,
+    ) -> TBareModel:
+        """
+        Get single model by document ID.
+
+        :param id_: Document ID.
+        :param transaction: Optional transaction to use.
+        :raises ModelNotFoundError: If no model was found by given id.
+        """
+        return cls.get_by_doc_id(id_, transaction=transaction)
 
 
 class BareSubCollection(ABC):
@@ -327,6 +377,9 @@ class BareSubCollection(ABC):
 
     @classmethod
     def model_for(cls, parent, model_class):
+        """
+        Returns the model for this subcollection.
+        """
         parent_props = parent.model_dump(by_alias=True)
 
         name = model_class.__name__
@@ -354,7 +407,9 @@ def _create(cls: Type[TBareSubModel], **kwargs) -> TBareSubModel:
 
     @classmethod
     def _get_col_ref(cls) -> CollectionReference:
-        """Returns the collection reference."""
+        """
+        Returns the collection reference.
+        """
         if cls.__collection__ is None or "{" in cls.__collection__:
             raise CollectionNotDefined(
                 f"{cls.__name__} is not properly prepared. "
@@ -364,6 +419,9 @@ def _get_col_ref(cls) -> CollectionReference:
 
     @classmethod
     def model_for(cls, parent):
+        """
+        Returns the model for this submodel.
+        """
         return cls.Collection.model_for(parent, cls)
 
 
@@ -371,12 +429,19 @@ class SubModel(BareSubModel):
     id: Optional[str] = None
 
     @classmethod
-    def get_by_id(cls: Type[TBareModel], id_: str) -> TBareModel:
+    def get_by_id(
+        cls: Type[TBareModel],
+        id_: str,
+        transaction: Optional[Transaction] = None,
+    ) -> TBareModel:
         """
         Get single item by document ID
+
+        :param id_: Document ID.
+        :param transaction: Optional transaction to use.
         :raises ModelNotFoundError:
         """
-        return cls.get_by_doc_id(id_)
+        return cls.get_by_doc_id(id_, transaction=transaction)
 
 
 class SubCollection(BareSubCollection, ABC):
diff --git a/firedantic/configurations.py b/firedantic/configurations.py
index 321a4af..2f9e277 100644
--- a/firedantic/configurations.py
+++ b/firedantic/configurations.py
@@ -1,6 +1,6 @@
 from typing import Any, Dict, Union
 
-from google.cloud.firestore_v1 import AsyncClient, Client
+from google.cloud.firestore_v1 import AsyncClient, AsyncTransaction, Client, Transaction
 
 CONFIGURATIONS: Dict[str, Any] = {}
 
@@ -15,3 +15,21 @@ def configure(db: Union[Client, AsyncClient], prefix: str = "") -> None:
 
     CONFIGURATIONS["db"] = db
     CONFIGURATIONS["prefix"] = prefix
+
+
+def get_transaction() -> Transaction:
+    """
+    Get a new Firestore transaction for the configured DB.
+    """
+    transaction = CONFIGURATIONS["db"].transaction()
+    assert isinstance(transaction, Transaction)
+    return transaction
+
+
+def get_async_transaction() -> AsyncTransaction:
+    """
+    Get a new Firestore transaction for the configured DB.
+    """
+    transaction = CONFIGURATIONS["db"].transaction()
+    assert isinstance(transaction, AsyncTransaction)
+    return transaction
diff --git a/firedantic/exceptions.py b/firedantic/exceptions.py
index af36989..5f8dbd4 100644
--- a/firedantic/exceptions.py
+++ b/firedantic/exceptions.py
@@ -1,16 +1,14 @@
 class ModelError(Exception):
     """Generic model error class."""
 
-    pass
-
 
 class InvalidDocumentID(ModelError):
-    pass
+    """Raised when a document ID is invalid."""
 
 
 class ModelNotFoundError(ModelError):
-    pass
+    """Raised when a model is not found."""
 
 
 class CollectionNotDefined(ModelError):
-    pass
+    """Raised when the model collection is not defined."""
diff --git a/firedantic/tests/tests_async/conftest.py b/firedantic/tests/tests_async/conftest.py
index ec1aaeb..09a4710 100644
--- a/firedantic/tests/tests_async/conftest.py
+++ b/firedantic/tests/tests_async/conftest.py
@@ -5,8 +5,8 @@
 import google.auth.credentials
 import pytest
 from google.cloud.firestore_admin_v1 import Field, FirestoreAdminClient
-from google.cloud.firestore_v1 import AsyncClient
-from pydantic import BaseModel, Extra, PrivateAttr
+from google.cloud.firestore_v1 import AsyncClient, AsyncTransaction, async_transactional
+from pydantic import BaseModel, PrivateAttr
 
 from firedantic import (
     AsyncBareModel,
@@ -16,7 +16,7 @@
     AsyncSubCollection,
     AsyncSubModel,
 )
-from firedantic.configurations import configure
+from firedantic.configurations import configure, get_async_transaction
 from firedantic.exceptions import ModelNotFoundError
 
 from unittest.mock import AsyncMock, Mock  # noqa isort: skip
@@ -30,7 +30,7 @@ class CustomIDModel(AsyncBareModel):
     bar: str
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class CustomIDModelExtra(AsyncBareModel):
@@ -42,7 +42,7 @@ class CustomIDModelExtra(AsyncBareModel):
     baz: str
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class CustomIDConflictModel(AsyncModel):
@@ -52,7 +52,24 @@ class CustomIDConflictModel(AsyncModel):
     bar: str
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
+
+
+class City(AsyncModel):
+    """City model used for test with transactions"""
+
+    __collection__ = "cities"
+    population: int
+
+    async def increment_population(self, increment: int = 1):
+        @async_transactional
+        async def _increment_population(transaction: AsyncTransaction) -> None:
+            await self.reload(transaction=transaction)
+            self.population += increment
+            await self.save(transaction=transaction)
+
+        t = get_async_transaction()
+        await _increment_population(transaction=t)
 
 
 class Owner(BaseModel):
@@ -62,7 +79,7 @@ class Owner(BaseModel):
     last_name: str
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class CompanyStats(AsyncBareSubModel):
@@ -99,7 +116,7 @@ class Company(AsyncModel):
     owner: Owner
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
     def stats(self) -> Type[CompanyStats]:
         return CompanyStats.model_for(self)  # type: ignore
@@ -115,7 +132,7 @@ class Product(AsyncModel):
     stock: int
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class Profile(AsyncModel):
@@ -127,7 +144,7 @@ class Profile(AsyncModel):
     photo_url: Optional[str] = None
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class TodoList(AsyncModel):
@@ -139,7 +156,7 @@ class TodoList(AsyncModel):
     items: List[str]
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class ExpiringModel(AsyncModel):
diff --git a/firedantic/tests/tests_async/test_model.py b/firedantic/tests/tests_async/test_model.py
index 501dad7..ed27c0d 100644
--- a/firedantic/tests/tests_async/test_model.py
+++ b/firedantic/tests/tests_async/test_model.py
@@ -2,17 +2,19 @@
 from uuid import uuid4
 
 import pytest
-from google.cloud.firestore import Query
+from google.cloud.firestore import Query, async_transactional
+from google.cloud.firestore_v1.async_transaction import AsyncTransaction
 from pydantic import Field, ValidationError
 
 import firedantic.operators as op
-from firedantic import AsyncModel
+from firedantic import AsyncModel, get_async_transaction
 from firedantic.exceptions import (
     CollectionNotDefined,
     InvalidDocumentID,
     ModelNotFoundError,
 )
 from firedantic.tests.tests_async.conftest import (
+    City,
     Company,
     CustomIDConflictModel,
     CustomIDModel,
@@ -535,3 +537,116 @@ async def test_save_with_exclude_unset(configure_db) -> None:
 
     data = document.to_dict()
     assert data == {"name": "", "photo_url": None}
+
+
+@pytest.mark.asyncio
+async def test_update_city_in_transaction(configure_db) -> None:
+    """
+    Test updating a model in a transaction. Test case from README.
+
+    :param: configure_db: pytest fixture
+    """
+
+    @async_transactional
+    async def decrement_population(
+        transaction: AsyncTransaction, city: City, decrement: int = 1
+    ):
+        await city.reload(transaction=transaction)
+        city.population = max(0, city.population - decrement)
+        await city.save(transaction=transaction)
+
+    c = City(id="SF", population=1)
+    await c.save()
+    await c.increment_population(increment=1)
+    assert c.population == 2
+
+    t = get_async_transaction()
+    await decrement_population(transaction=t, city=c, decrement=5)
+    assert c.population == 0
+
+
+@pytest.mark.asyncio
+async def test_delete_in_transaction(configure_db) -> None:
+    """
+    Test deleting a model in a transaction.
+
+    :param: configure_db: pytest fixture
+    """
+
+    @async_transactional
+    async def delete_in_transaction(
+        transaction: AsyncTransaction, profile_id: str
+    ) -> None:
+        """Deletes a Profile in a transaction."""
+        profile = await Profile.get_by_id(profile_id, transaction=transaction)
+        await profile.delete(transaction=transaction)
+
+    p = Profile(name="Foo")
+    await p.save()
+    assert p.id
+
+    t = get_async_transaction()
+    await delete_in_transaction(t, p.id)
+
+    with pytest.raises(ModelNotFoundError):
+        await Profile.get_by_id(p.id)
+
+
+@pytest.mark.asyncio
+async def test_update_model_in_transaction(configure_db) -> None:
+    """
+    Test updating a model in a transaction.
+
+    :param: configure_db: pytest fixture
+    """
+
+    @async_transactional
+    async def update_in_transaction(
+        transaction: AsyncTransaction, profile_id: str, name: str
+    ) -> None:
+        """Updates a Profile in a transaction."""
+        profile = Profile(id=profile_id)
+        await profile.reload(transaction=transaction)
+        profile.name = name
+        await profile.save(transaction=transaction)
+
+    p = Profile(name="Foo")
+    await p.save()
+
+    t = get_async_transaction()
+    await update_in_transaction(t, p.id, name="Bar")
+    await p.reload()
+    assert p.name == "Bar"
+
+
+@pytest.mark.asyncio
+async def test_update_submodel_in_transaction(configure_db) -> None:
+    """
+    Test Updating a submodel in a transaction.
+
+    :param: configure_db: pytest fixture
+    """
+
+    @async_transactional
+    async def update_submodel_in_transaction(
+        transaction: AsyncTransaction, user_id: str, period: str
+    ) -> UserStats:
+        """Updates a UserStats in a transaction."""
+        u = await User.get_by_id(user_id, transaction=transaction)
+        us = UserStats.model_for(u)
+        user_stats: UserStats = await us.get_by_id(period)  # pylint: disable=no-member
+        user_stats.purchases += 1
+        await user_stats.save(transaction=transaction)
+        return user_stats
+
+    u = User(name="Foo")
+    await u.save()
+    assert u.id
+    us = UserStats.model_for(u)
+    await us(id="2021", purchases=42).save()  # pylint: disable=no-member
+
+    t = get_async_transaction()
+    user_stats = await update_submodel_in_transaction(t, u.id, "2021")
+    assert isinstance(user_stats, UserStats)
+    assert user_stats.purchases == 43
+    assert await get_user_purchases(u.id) == 43
diff --git a/firedantic/tests/tests_sync/conftest.py b/firedantic/tests/tests_sync/conftest.py
index ea7d4c2..8debfc4 100644
--- a/firedantic/tests/tests_sync/conftest.py
+++ b/firedantic/tests/tests_sync/conftest.py
@@ -5,8 +5,8 @@
 import google.auth.credentials
 import pytest
 from google.cloud.firestore_admin_v1 import Field, FirestoreAdminClient
-from google.cloud.firestore_v1 import Client
-from pydantic import BaseModel, Extra, PrivateAttr
+from google.cloud.firestore_v1 import Client, Transaction, transactional
+from pydantic import BaseModel, PrivateAttr
 
 from firedantic import (
     BareModel,
@@ -16,7 +16,7 @@
     SubCollection,
     SubModel,
 )
-from firedantic.configurations import configure
+from firedantic.configurations import configure, get_transaction
 from firedantic.exceptions import ModelNotFoundError
 
 from unittest.mock import Mock, Mock  # noqa isort: skip
@@ -30,7 +30,7 @@ class CustomIDModel(BareModel):
     bar: str
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class CustomIDModelExtra(BareModel):
@@ -42,7 +42,7 @@ class CustomIDModelExtra(BareModel):
     baz: str
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class CustomIDConflictModel(Model):
@@ -52,7 +52,24 @@ class CustomIDConflictModel(Model):
     bar: str
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
+
+
+class City(Model):
+    """City model used for test with transactions"""
+
+    __collection__ = "cities"
+    population: int
+
+    def increment_population(self, increment: int = 1):
+        @transactional
+        def _increment_population(transaction: Transaction) -> None:
+            self.reload(transaction=transaction)
+            self.population += increment
+            self.save(transaction=transaction)
+
+        t = get_transaction()
+        _increment_population(transaction=t)
 
 
 class Owner(BaseModel):
@@ -62,7 +79,7 @@ class Owner(BaseModel):
     last_name: str
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class CompanyStats(BareSubModel):
@@ -99,7 +116,7 @@ class Company(Model):
     owner: Owner
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
     def stats(self) -> Type[CompanyStats]:
         return CompanyStats.model_for(self)  # type: ignore
@@ -115,7 +132,7 @@ class Product(Model):
     stock: int
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class Profile(Model):
@@ -127,7 +144,7 @@ class Profile(Model):
     photo_url: Optional[str] = None
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class TodoList(Model):
@@ -139,7 +156,7 @@ class TodoList(Model):
     items: List[str]
 
     class Config:
-        extra = Extra.forbid
+        extra = "forbid"
 
 
 class ExpiringModel(Model):
diff --git a/firedantic/tests/tests_sync/test_model.py b/firedantic/tests/tests_sync/test_model.py
index 0f62a5b..37e27a4 100644
--- a/firedantic/tests/tests_sync/test_model.py
+++ b/firedantic/tests/tests_sync/test_model.py
@@ -2,17 +2,19 @@
 from uuid import uuid4
 
 import pytest
-from google.cloud.firestore import Query
+from google.cloud.firestore import Query, transactional
+from google.cloud.firestore_v1.transaction import Transaction
 from pydantic import Field, ValidationError
 
 import firedantic.operators as op
-from firedantic import Model
+from firedantic import Model, get_transaction
 from firedantic.exceptions import (
     CollectionNotDefined,
     InvalidDocumentID,
     ModelNotFoundError,
 )
 from firedantic.tests.tests_sync.conftest import (
+    City,
     Company,
     CustomIDConflictModel,
     CustomIDModel,
@@ -500,3 +502,108 @@ def test_save_with_exclude_unset(configure_db) -> None:
 
     data = document.to_dict()
     assert data == {"name": "", "photo_url": None}
+
+
+def test_update_city_in_transaction(configure_db) -> None:
+    """
+    Test updating a model in a transaction. Test case from README.
+
+    :param: configure_db: pytest fixture
+    """
+
+    @transactional
+    def decrement_population(transaction: Transaction, city: City, decrement: int = 1):
+        city.reload(transaction=transaction)
+        city.population = max(0, city.population - decrement)
+        city.save(transaction=transaction)
+
+    c = City(id="SF", population=1)
+    c.save()
+    c.increment_population(increment=1)
+    assert c.population == 2
+
+    t = get_transaction()
+    decrement_population(transaction=t, city=c, decrement=5)
+    assert c.population == 0
+
+
+def test_delete_in_transaction(configure_db) -> None:
+    """
+    Test deleting a model in a transaction.
+
+    :param: configure_db: pytest fixture
+    """
+
+    @transactional
+    def delete_in_transaction(transaction: Transaction, profile_id: str) -> None:
+        """Deletes a Profile in a transaction."""
+        profile = Profile.get_by_id(profile_id, transaction=transaction)
+        profile.delete(transaction=transaction)
+
+    p = Profile(name="Foo")
+    p.save()
+    assert p.id
+
+    t = get_transaction()
+    delete_in_transaction(t, p.id)
+
+    with pytest.raises(ModelNotFoundError):
+        Profile.get_by_id(p.id)
+
+
+def test_update_model_in_transaction(configure_db) -> None:
+    """
+    Test updating a model in a transaction.
+
+    :param: configure_db: pytest fixture
+    """
+
+    @transactional
+    def update_in_transaction(
+        transaction: Transaction, profile_id: str, name: str
+    ) -> None:
+        """Updates a Profile in a transaction."""
+        profile = Profile(id=profile_id)
+        profile.reload(transaction=transaction)
+        profile.name = name
+        profile.save(transaction=transaction)
+
+    p = Profile(name="Foo")
+    p.save()
+
+    t = get_transaction()
+    update_in_transaction(t, p.id, name="Bar")
+    p.reload()
+    assert p.name == "Bar"
+
+
+def test_update_submodel_in_transaction(configure_db) -> None:
+    """
+    Test Updating a submodel in a transaction.
+
+    :param: configure_db: pytest fixture
+    """
+
+    @transactional
+    def update_submodel_in_transaction(
+        transaction: Transaction, user_id: str, period: str
+    ) -> UserStats:
+        """Updates a UserStats in a transaction."""
+        u = User.get_by_id(user_id, transaction=transaction)
+        us = UserStats.model_for(u)
+        user_stats: UserStats = us.get_by_id(period)  # pylint: disable=no-member
+        user_stats.purchases += 1
+        user_stats.save(transaction=transaction)
+        return user_stats
+
+    u = User(name="Foo")
+    u.save()
+    assert u.id
+    us = UserStats.model_for(u)
+    us(id="2021", purchases=42).save()  # pylint: disable=no-member
+
+    t = get_transaction()
+    user_stats = update_submodel_in_transaction(t, u.id, "2021")
+    assert isinstance(user_stats, UserStats)
+    assert user_stats.purchases == 43
+    assert get_user_purchases(u.id) == 43
diff --git a/pyproject.toml b/pyproject.toml
index 36e2901..18e2cc6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "firedantic"
-version = "0.10.0"
+version = "0.11.0"
 description = "Pydantic base models for Firestore"
 authors = ["IOXIO Ltd"]
 license = "BSD-3-Clause"
diff --git a/unasync.py b/unasync.py
index e6ac175..ffa7887 100644
--- a/unasync.py
+++ b/unasync.py
@@ -5,6 +5,13 @@
 from pathlib import Path
 
 SUBS = [
+    ("get_async_transaction", "get_transaction"),
+    (
+        "from google.cloud.firestore_v1.async_transaction",
+        "from google.cloud.firestore_v1.transaction",
+    ),
+    ("async_transactional", "transactional"),
+    ("AsyncTransaction", "Transaction"),
     ("google.cloud.firestore_v1.async_query", "google.cloud.firestore_v1.base_query"),
     ("AsyncQuery", "BaseQuery"),
     ("AsyncCollectionReference", "CollectionReference"),