diff --git a/api/features/views.py b/api/features/views.py
index 9ddf9f6b590e..f4477ee77b39 100644
--- a/api/features/views.py
+++ b/api/features/views.py
@@ -875,7 +875,12 @@ def get_queryset(self):  # type: ignore[no-untyped-def]
         if getattr(self, "swagger_fake_view", False):
             return FeatureState.objects.none()
 
-        return super().get_queryset().filter(identity__pk=self.kwargs["identity_pk"])  # type: ignore[no-untyped-call]
+        try:
+            identity_pk = int(self.kwargs["identity_pk"])
+        except ValueError:
+            raise NotFound("Identity not found.")
+
+        return super().get_queryset().filter(identity__pk=identity_pk)  # type: ignore[no-untyped-call]
 
     @action(methods=["GET"], detail=False)
     def all(self, request, *args, **kwargs):  # type: ignore[no-untyped-def]
diff --git a/api/tests/unit/features/test_unit_features_views.py b/api/tests/unit/features/test_unit_features_views.py
index f47d3951d262..402f210ab181 100644
--- a/api/tests/unit/features/test_unit_features_views.py
+++ b/api/tests/unit/features/test_unit_features_views.py
@@ -273,6 +273,24 @@ def test_delete_identity_feature_state__existing_state__creates_audit_log(
     )
 
 
+def test_list_identity_feature_states__non_integer_identity_pk__returns_404(
+    environment: Environment,
+    admin_client_new: APIClient,
+) -> None:
+    # Given
+    url = reverse(
+        "api-v1:environments:identity-featurestates-list",
+        args=[environment.api_key, "org_notanumber"],
+    )
+
+    # When
+    response = admin_client_new.get(url)
+
+    # Then
+    assert response.status_code == status.HTTP_404_NOT_FOUND
+    assert response.json() == {"detail": "Identity not found."}
+
+
 def test_create_feature__tags_from_different_project__returns_400(
     project: Project,
     admin_client_new: APIClient,