diff --git a/backend/sophon/core/views.py b/backend/sophon/core/views.py
index 74e0648..9a20695 100644
--- a/backend/sophon/core/views.py
+++ b/backend/sophon/core/views.py
@@ -262,6 +262,9 @@ class ResearchGroupViewSet(WriteSophonViewSet):
         """
         group = models.ResearchGroup.objects.get(pk=pk)
 
+        if self.request.user.is_anonymous:
+            return Response(status=s.HTTP_401_UNAUTHORIZED)
+
         # Raise an error if the group doesn't allow member joins
         if group.access != "OPEN":
             return Response(status=s.HTTP_403_FORBIDDEN)
@@ -283,6 +286,9 @@ class ResearchGroupViewSet(WriteSophonViewSet):
         """
         group = models.ResearchGroup.objects.get(pk=pk)
 
+        if self.request.user.is_anonymous:
+            return Response(status=s.HTTP_401_UNAUTHORIZED)
+
         # Raise an error if the user is the owner of the group
         if self.request.user == group.owner:
             return Response(status=s.HTTP_403_FORBIDDEN)