diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index de737fc3b..5ca1ad55f 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -1608,7 +1608,7 @@ class ModelSerializer(Serializer):
 
         unique_constraint_by_fields = {
             constraint.fields: constraint
-            for model_cls in (self.Meta.model, *self.Meta.model._meta.parents)
+            for model_cls in (*self.Meta.model._meta.parents, self.Meta.model)
             for constraint in model_cls._meta.constraints
             if isinstance(constraint, models.UniqueConstraint)
         }