diff --git a/src/validate.rs b/src/validate.rs
index f9765bf2b..daecfc2c6 100644
--- a/src/validate.rs
+++ b/src/validate.rs
@@ -1212,6 +1212,14 @@ fn validate_trusted_publishing(data: &Data, errors: &mut Vec<String>) {
                 ));
             }
 
+            // Validate that the environment referenced in crates-io exists
+            if !repo.environments.contains_key(&publishing.environment) {
+                return Err(anyhow::anyhow!(
+                    "Repository `{repo_name}` configures trusted publishing with environment `{}` which is not defined in the repository's environments. Please add an environment with this name in the repository configuration.",
+                    publishing.environment
+                ));
+            }
+
             for krate in &publishing.crates {
                 if let Some(prev_repo) = crates.insert(krate.clone(), repo_name.clone()) {
                     return Err(anyhow::anyhow!(
diff --git a/tests/static-api/_expected/v1/repos.json b/tests/static-api/_expected/v1/repos.json
index fdf43c4dd..ae7d5d782 100644
--- a/tests/static-api/_expected/v1/repos.json
+++ b/tests/static-api/_expected/v1/repos.json
@@ -103,7 +103,14 @@
           ]
         }
       ],
-      "environments": {},
+      "environments": {
+        "deploy": {
+          "branches": [
+            "main"
+          ],
+          "tags": []
+        }
+      },
       "archived": false,
       "private": false,
       "auto_merge_enabled": true
diff --git a/tests/static-api/_expected/v1/repos/some_repo.json b/tests/static-api/_expected/v1/repos/some_repo.json
index 6e94c23b9..504838674 100644
--- a/tests/static-api/_expected/v1/repos/some_repo.json
+++ b/tests/static-api/_expected/v1/repos/some_repo.json
@@ -71,7 +71,14 @@
       ]
     }
   ],
-  "environments": {},
+  "environments": {
+    "deploy": {
+      "branches": [
+        "main"
+      ],
+      "tags": []
+    }
+  },
   "archived": false,
   "private": false,
   "auto_merge_enabled": true
diff --git a/tests/static-api/repos/test-org/some_repo.toml b/tests/static-api/repos/test-org/some_repo.toml
index 4ba54187f..0bd6d6673 100644
--- a/tests/static-api/repos/test-org/some_repo.toml
+++ b/tests/static-api/repos/test-org/some_repo.toml
@@ -11,6 +11,9 @@ pattern = "master"
 ci-checks = ["CI"]
 allowed-merge-teams = ["foo"]
 
+[environments.deploy]
+branches = ["main"]
+
 [[crates-io]]
 crates = ["my-crate", "my-crate-2"]
 publish-workflow = "ci.yml"