diff --git a/biscuit/apps/alsijil/views.py b/biscuit/apps/alsijil/views.py
index 5cf9cfb389385c531381859339f88b33ab26e844..d5db8e064fd92d5ffba374a1438095da13c7b2b3 100644
--- a/biscuit/apps/alsijil/views.py
+++ b/biscuit/apps/alsijil/views.py
@@ -81,10 +81,11 @@ def group_week(request: HttpRequest, week: Optional[int] = None) -> HttpResponse
 
     periods_by_day_unsorted = {}
     if group:
-        for lesson in group.lessons.filter(date_start__lte=week_start, date_end__gte=week_end):
-            for lesson_period in lesson.lesson_periods.all():
-                periods_by_day_unsorted.setdefault(
-                    lesson_period.period.weekday, []).append(lesson_period)
+        for act_group in [group] + group.child_groups.all():
+            for lesson in act_group.lessons.filter(date_start__lte=week_start, date_end__gte=week_end):
+                for lesson_period in lesson.lesson_periods.all():
+                    periods_by_day_unsorted.setdefault(
+                        lesson_period.period.weekday, []).append(lesson_period)
 
     periods_by_day = OrderedDict()
     for weekday, periods in sorted(periods_by_day_unsorted.items()):