diff --git a/backend/app/models/assignment.py b/backend/app/models/assignment.py
index 76fab8e..798610b 100644
--- a/backend/app/models/assignment.py
+++ b/backend/app/models/assignment.py
@@ -35,4 +35,4 @@ class Assignment(Base):
     participant: Mapped["Participant"] = relationship("Participant", back_populates="assignments")
     challenge: Mapped["Challenge"] = relationship("Challenge", back_populates="assignments")
     event: Mapped["Event | None"] = relationship("Event", back_populates="assignments")
-    dispute: Mapped["Dispute | None"] = relationship("Dispute", back_populates="assignment", uselist=False)
+    dispute: Mapped["Dispute | None"] = relationship("Dispute", back_populates="assignment", uselist=False, cascade="all, delete-orphan", passive_deletes=True)