diff --git a/prisma/migrations/20251103161018_add_ondelete_cascade_to_activity_groupid/migration.sql b/prisma/migrations/20251103161018_add_ondelete_cascade_to_activity_groupid/migration.sql
new file mode 100644
index 0000000..e4dfcaf
--- /dev/null
+++ b/prisma/migrations/20251103161018_add_ondelete_cascade_to_activity_groupid/migration.sql
@@ -0,0 +1,5 @@
+-- DropForeignKey
+ALTER TABLE "Activity" DROP CONSTRAINT "Activity_groupId_fkey";
+
+-- AddForeignKey
+ALTER TABLE "Activity" ADD CONSTRAINT "Activity_groupId_fkey" FOREIGN KEY ("groupId") REFERENCES "Group"("id") ON DELETE CASCADE ON UPDATE CASCADE;
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 820609a..b20aa0e 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -116,7 +116,7 @@ model ExpensePaidFor {
 
 model Activity {
   id            String       @id
-  group         Group        @relation(fields: [groupId], references: [id])
+  group         Group        @relation(fields: [groupId], references: [id], onDelete: Cascade)
   groupId       String
   time          DateTime     @default(now())
   activityType  ActivityType