diff --git a/rating_api/routes/lecturer.py b/rating_api/routes/lecturer.py
index 3a10e38..eb3b770 100644
--- a/rating_api/routes/lecturer.py
+++ b/rating_api/routes/lecturer.py
@@ -138,7 +138,7 @@ async def get_lecturers(
     if "general" in order_by:
         result.lecturers.sort(key=lambda item: (item.mark_general is None, item.mark_general))
     if subject:
-        result.lecturers = [lecturer for lecturer in result.lecturers if subject in lecturer.subjects]
+        result.lecturers = [lecturer for lecturer in result.lecturers if lecturer.subjects and subject in lecturer.subjects]
     result.total = len(result.lecturers)
     return result