diff --git a/database/migration/20260425_study_cascade_delete.sql b/database/migration/20260425_study_cascade_delete.sql
new file mode 100644
index 000000000..0c6333602
--- /dev/null
+++ b/database/migration/20260425_study_cascade_delete.sql
@@ -0,0 +1,24 @@
+--
+-- Add ON DELETE CASCADE to all FK constraints referencing study(id)
+-- so that deleting a study automatically removes all dependent records.
+--
+
+ALTER TABLE public.repo
+  DROP CONSTRAINT "repo_studyId_fkey",
+  ADD CONSTRAINT "repo_studyId_fkey"
+    FOREIGN KEY (study_id) REFERENCES public.study(id) ON DELETE CASCADE;
+
+ALTER TABLE public.study_fitbit_credentials
+  DROP CONSTRAINT "study_fitbit_credentials_studyId_fkey",
+  ADD CONSTRAINT "study_fitbit_credentials_studyId_fkey"
+    FOREIGN KEY (study_id) REFERENCES public.study(id) ON DELETE CASCADE;
+
+ALTER TABLE public.study_invite
+  DROP CONSTRAINT "study_invite_studyId_fkey",
+  ADD CONSTRAINT "study_invite_studyId_fkey"
+    FOREIGN KEY (study_id) REFERENCES public.study(id) ON DELETE CASCADE;
+
+ALTER TABLE public.study_subject
+  DROP CONSTRAINT "study_subject_studyId_fkey",
+  ADD CONSTRAINT "study_subject_studyId_fkey"
+    FOREIGN KEY (study_id) REFERENCES public.study(id) ON DELETE CASCADE;
diff --git a/database/studyu-schema.sql b/database/studyu-schema.sql
index 3eb887cae..90612a30b 100644
--- a/database/studyu-schema.sql
+++ b/database/studyu-schema.sql
@@ -640,7 +640,7 @@ ALTER TABLE ONLY "public"."subject_progress"
 
 
 ALTER TABLE ONLY "public"."repo"
-    ADD CONSTRAINT "repo_studyId_fkey" FOREIGN KEY ("study_id") REFERENCES "public"."study"("id");
+    ADD CONSTRAINT "repo_studyId_fkey" FOREIGN KEY ("study_id") REFERENCES "public"."study"("id") ON DELETE CASCADE;
 
 
 
@@ -650,12 +650,12 @@ ALTER TABLE ONLY "public"."repo"
 
 
 ALTER TABLE ONLY "public"."study_fitbit_credentials"
-    ADD CONSTRAINT "study_fitbit_credentials_studyId_fkey" FOREIGN KEY ("study_id") REFERENCES "public"."study"("id");
+    ADD CONSTRAINT "study_fitbit_credentials_studyId_fkey" FOREIGN KEY ("study_id") REFERENCES "public"."study"("id") ON DELETE CASCADE;
 
 
 
 ALTER TABLE ONLY "public"."study_invite"
-    ADD CONSTRAINT "study_invite_studyId_fkey" FOREIGN KEY ("study_id") REFERENCES "public"."study"("id");
+    ADD CONSTRAINT "study_invite_studyId_fkey" FOREIGN KEY ("study_id") REFERENCES "public"."study"("id") ON DELETE CASCADE;
 
 
 
@@ -665,7 +665,7 @@ ALTER TABLE ONLY "public"."study_subject"
 
 
 ALTER TABLE ONLY "public"."study_subject"
-    ADD CONSTRAINT "study_subject_studyId_fkey" FOREIGN KEY ("study_id") REFERENCES "public"."study"("id");
+    ADD CONSTRAINT "study_subject_studyId_fkey" FOREIGN KEY ("study_id") REFERENCES "public"."study"("id") ON DELETE CASCADE;