diff --git a/backend/tests/conftest.py b/backend/tests/conftest.py
index 183de4c..8488667 100644
--- a/backend/tests/conftest.py
+++ b/backend/tests/conftest.py
@@ -26,6 +26,14 @@ pytest_plugins = [
 ]
 
 
+@pytest.fixture(autouse=True)
+def _cleanup_dependency_overrides():
+    """Ensure dependency_overrides are cleaned up after each test."""
+    from app.main import app
+    yield
+    app.dependency_overrides.clear()
+
+
 @pytest.fixture(autouse=True)
 def add_api_key_filter():
     root_logger = logging.getLogger()