diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index fe214d7d..430d0265 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -14,3 +14,11 @@ repos:
     rev: 7.1.1
     hooks:
     -   id: flake8
+-   repo: https://github.com/pre-commit/mirrors-mypy
+    rev: v1.11.2
+    hooks:
+    -   id: mypy
+        additional_dependencies:
+            - types-colorama
+            - types-PyYAML
+            - types-requests
diff --git a/mypy.ini b/mypy.ini
new file mode 100644
index 00000000..b1e5e09d
--- /dev/null
+++ b/mypy.ini
@@ -0,0 +1,23 @@
+[mypy-txaio.*]
+ignore_missing_imports = True
+
+[mypy-influxdb.*]
+ignore_missing_imports = True
+
+[mypy-autobahn.*]
+ignore_missing_imports = True
+
+[mypy-deprecation.*]
+ignore_missing_imports = True
+
+[mypy-coverage.*]
+ignore_missing_imports = True
+
+[mypy-so3g.*]
+ignore_missing_imports = True
+
+[mypy-progress.*]
+ignore_missing_imports = True
+
+[mypy-spt3g.*]
+ignore_missing_imports = True
diff --git a/ocs/__init__.py b/ocs/__init__.py
index 2cdec324..6baff5a7 100644
--- a/ocs/__init__.py
+++ b/ocs/__init__.py
@@ -8,7 +8,7 @@
 try:
     # If setuptools_scm is installed (e.g. in a development environment with
     # an editable install), then use it to determine the version dynamically.
-    from setuptools_scm import get_version
+    from setuptools_scm import get_version  # type: ignore
 
     # This will fail with LookupError if the package is not installed in
     # editable mode or if Git is not installed.
@@ -16,7 +16,7 @@
 except (ImportError, LookupError):
     # As a fallback, use the version that is hard-coded in the file.
     try:
-        from ocs._version import __version__  # noqa: F401
+        from ocs._version import __version__  # type: ignore # noqa: F401
     except ModuleNotFoundError:
         # The user is probably trying to run this without having installed
         # the package, so complain.
diff --git a/ocs/agents/aggregator/agent.py b/ocs/agents/aggregator/agent.py
index b1e2301a..1663efac 100644
--- a/ocs/agents/aggregator/agent.py
+++ b/ocs/agents/aggregator/agent.py
@@ -122,7 +122,7 @@ def record(self, session: ocs_agent.OpSession, params):
         except PermissionError:
             self.log.error("Unable to intialize Aggregator due to permission "
                            "error, stopping twisted reactor")
-            reactor.callFromThread(reactor.stop)
+            reactor.callFromThread(reactor.stop)  # type: ignore
             return False, "Aggregation not started"
 
         while self.aggregate:
diff --git a/ocs/agents/registry/agent.py b/ocs/agents/registry/agent.py
index 4ead257f..7ad19d98 100644
--- a/ocs/agents/registry/agent.py
+++ b/ocs/agents/registry/agent.py
@@ -6,6 +6,8 @@
 from ocs.ocs_feed import Feed
 import argparse
 
+from typing import Dict, Any, Optional
+
 
 class RegisteredAgent:
     """
@@ -28,15 +30,15 @@ class RegisteredAgent:
                 docs from the ``ocs_agent`` module
     """
 
-    def __init__(self, feed):
+    def __init__(self, feed: Dict[str, Any]) -> None:
         self.expired = False
-        self.time_expired = None
+        self.time_expired: Optional[float] = None
         self.last_updated = time.time()
-        self.op_codes = {}
-        self.agent_class = feed.get('agent_class')
-        self.agent_address = feed['agent_address']
+        self.op_codes: Dict[str, int] = {}
+        self.agent_class: Optional[str] = feed.get('agent_class')
+        self.agent_address: str = feed['agent_address']
 
-    def refresh(self, op_codes=None):
+    def refresh(self, op_codes: Optional[Dict[str, int]] = None) -> None:
         self.expired = False
         self.time_expired = None
         self.last_updated = time.time()
@@ -44,13 +46,13 @@ def refresh(self, op_codes=None):
         if op_codes:
             self.op_codes.update(op_codes)
 
-    def expire(self):
+    def expire(self) -> None:
         self.expired = True
         self.time_expired = time.time()
         for k in self.op_codes:
             self.op_codes[k] = OpCode.EXPIRED.value
 
-    def encoded(self):
+    def encoded(self) -> Dict[str, Any]:
         return {
             'expired': self.expired,
             'time_expired': self.time_expired,
@@ -85,7 +87,7 @@ class Registry:
                 as expired.
     """
 
-    def __init__(self, agent, args):
+    def __init__(self, agent: ocs_agent.OCSAgent, args: argparse.Namespace) -> None:
         self.log = agent.log
         self.agent = agent
         self.wait_time = args.wait_time
@@ -94,7 +96,7 @@ def __init__(self, agent, args):
         self._run = False
 
         # Dict containing agent_data for each registered agent
-        self.registered_agents = {}
+        self.registered_agents: Dict[str, RegisteredAgent] = {}
         self.agent_timeout = 5.0  # Removes agent after 5 seconds of no heartbeat.
 
         self.agent.subscribe_on_start(
@@ -108,7 +110,7 @@ def __init__(self, agent, args):
         self.agent.register_feed('agent_operations', record=True,
                                  agg_params=agg_params, buffer_time=0)
 
-    def _register_heartbeat(self, _data):
+    def _register_heartbeat(self, _data) -> None:
         """
             Function that is called whenever a heartbeat is received from an agent.
             It will update that agent in the Registry's registered_agent dict.
@@ -124,7 +126,7 @@ def _register_heartbeat(self, _data):
         if publish:
             self._publish_agent_ops(reg_agent)
 
-    def _publish_agent_ops(self, reg_agent):
+    def _publish_agent_ops(self, reg_agent: RegisteredAgent) -> None:
         """Publish a registered agent's OpCodes.
 
         Args:
@@ -150,7 +152,11 @@ def _publish_agent_ops(self, reg_agent):
 
     @ocs_agent.param('test_mode', default=False, type=bool)
     @inlineCallbacks
-    def main(self, session: ocs_agent.OpSession, params):
+    def main(
+        self,
+        session: ocs_agent.OpSession,
+        params: Optional[Dict[str, Any]]
+    ) -> ocs_agent.InlineCallbackOpType:
         """main(test_mode=False)
 
         **Process** - Main run process for the Registry agent. This will loop
@@ -214,13 +220,17 @@ def main(self, session: ocs_agent.OpSession, params):
                 for agent in self.registered_agents.values():
                     self._publish_agent_ops(agent)
 
-            if params['test_mode']:
+            if params['test_mode']:  # type: ignore
                 break
 
         return True, "Stopped registry main process"
 
     @inlineCallbacks
-    def _stop_main(self, session, params):
+    def _stop_main(
+        self,
+        session: ocs_agent.OpSession,
+        params: Optional[Dict[str, Any]]
+    ) -> ocs_agent.InlineCallbackOpType:
         """Stop function for the 'main' process."""
         yield
         if self._run:
@@ -240,7 +250,7 @@ def _register_agent(self, session, agent_data):
         return True, "'register_agent' is deprecated"
 
 
-def make_parser(parser=None):
+def make_parser(parser: Optional[argparse.ArgumentParser] = None) -> argparse.ArgumentParser:
     if parser is None:
         parser = argparse.ArgumentParser()
     pgroup = parser.add_argument_group('Agent Options')
@@ -249,7 +259,7 @@ def make_parser(parser=None):
     return parser
 
 
-def main(args=None):
+def main(args=None) -> None:
     parser = make_parser()
     args = site_config.parse_args(agent_class='RegistryAgent',
                                   parser=parser,
diff --git a/ocs/ocs_agent.py b/ocs/ocs_agent.py
index 5f17a002..315b0fad 100644
--- a/ocs/ocs_agent.py
+++ b/ocs/ocs_agent.py
@@ -1,8 +1,10 @@
+from __future__ import annotations
 import ocs
 
 import txaio
 txaio.use_twisted()
 
+
 from twisted.application.internet import backoffPolicy
 from twisted.internet import reactor, task, threads
 from twisted.internet.defer import inlineCallbacks, Deferred, DeferredList, FirstError, maybeDeferred
@@ -18,6 +20,7 @@
 from autobahn.exception import Disconnected
 from .ocs_twisted import in_reactor_context
 
+import argparse
 import json
 import math
 import time
@@ -28,9 +31,20 @@
 from ocs import client_t
 from ocs import ocs_feed
 from ocs.base import OpCode
+from typing import Tuple, Optional, Callable, Dict, Any, Union, TypeVar, Generator
+
+
+OpFuncType = Union[
+    Callable[["OpSession", Optional[Dict[str, Any]]], Tuple[bool, str]],
+    Callable[["OpSession", Optional[Dict[str, Any]]], Deferred[Tuple[bool, str]]],
+]
+InlineCallbackOpType = Generator[Any, Any, Tuple[bool, str]]
 
 
-def init_site_agent(args, address=None):
+def init_site_agent(
+    args: argparse.Namespace,
+    address: Optional[str] = None
+) -> Tuple[OCSAgent, ApplicationRunner]:
     """
     Create ApplicationSession and ApplicationRunner instances, set up
     to communicate on the chosen WAMP realm.
@@ -432,8 +446,15 @@ def _management_handler(self, q, **kwargs):
         if q == 'get_agent_class':
             return self.class_name
 
-    def register_task(self, name, func, aborter=None, blocking=True,
-                      aborter_blocking=None, startup=False):
+    def register_task(
+        self,
+        name: str,
+        func: OpFuncType,
+        aborter: Optional[OpFuncType] = None,
+        blocking: bool = True,
+        aborter_blocking: Optional[bool] = None,
+        startup: Union[bool, Dict[str, Any]] = False
+    ) -> None:
         """Register a Task for this agent.
 
         Args:
@@ -474,8 +495,15 @@ def register_task(self, name, func, aborter=None, blocking=True,
         if startup is not False:
             self.startup_ops.append(('task', name, startup))
 
-    def register_process(self, name, start_func, stop_func, blocking=True,
-                         stopper_blocking=None, startup=False):
+    def register_process(
+        self,
+        name: str,
+        start_func: OpFuncType,
+        stop_func: OpFuncType,
+        blocking: bool = True,
+        stopper_blocking: Optional[bool] = None,
+        startup: Union[bool, Dict[str, Any]] = False
+    ) -> None:
         """Register a Process for this agent.
 
         Args:
@@ -1520,7 +1548,10 @@ def check_for_strays(self, ignore=[]):
             raise ParamError(f"params included unexpected values: {weird_args}")
 
 
-def param(key, **kwargs):
+F = TypeVar('F')
+
+
+def param(key, **kwargs) -> Callable[[F], F]:
     """Decorator for Agent operation functions to assist with checking
     params prior to actually trying to execute the code.  Example::
 
diff --git a/ocs/py.typed b/ocs/py.typed
new file mode 100644
index 00000000..e69de29b