diff --git a/aleksis/apps/chronos/models.py b/aleksis/apps/chronos/models.py
index 9533ce1b0c83519f4b6d3936235e660f0f706e07..732c95d53a22ecdb3764b4f71bf55a5b3aa6e410 100644
--- a/aleksis/apps/chronos/models.py
+++ b/aleksis/apps/chronos/models.py
@@ -1533,7 +1533,7 @@ class LessonEvent(CalendarEvent):
             .get_objects(request, params)
             .not_instance_of(SupervisionEvent)
             .select_related("subject", "course")
-            .prefetch_related("groups", "teachers", "rooms")
+            .prefetch_related("groups", "teachers", "rooms", "groups__members")
         )
 
         if request and not has_person(request.user):