diff --git a/core/concepts/serializers.py b/core/concepts/serializers.py
index dbec928f..77774717 100644
--- a/core/concepts/serializers.py
+++ b/core/concepts/serializers.py
@@ -297,7 +297,7 @@ def get_mappings(self, obj):  # pylint: disable=too-many-locals
             ) if is_collection else obj.get_bidirectional_mappings()
             if not include_retired:
                 mappings = mappings.filter(retired=False)
-            return serializer_class(mappings, many=True).data
+            return serializer_class(mappings.order_by('id'), many=True).data
         if self.include_direct_mappings:
             mappings = obj.get_unidirectional_mappings_for_collection(
                 parent_uri, collection_version) if is_collection else obj.get_unidirectional_mappings()
@@ -307,7 +307,7 @@ def get_mappings(self, obj):  # pylint: disable=too-many-locals
                 mappings = mappings.filter(to_source_url__in=target_repo_urls)
             if not include_retired:
                 mappings = mappings.filter(retired=False)
-            return serializer_class(mappings, many=True).data
+            return serializer_class(mappings.order_by('id'), many=True).data
 
         return []
 
@@ -726,11 +726,11 @@ def get_mappings(self, obj):
             mappings = obj.get_bidirectional_mappings_for_collection(
                 parent_uri, collection_version
             ) if is_collection else obj.get_bidirectional_mappings()
-            return MappingDetailSerializer(mappings, many=True, context=context).data
+            return MappingDetailSerializer(mappings.order_by('id'), many=True, context=context).data
         if self.include_direct_mappings:
             mappings = obj.get_unidirectional_mappings_for_collection(
                 parent_uri, collection_version) if is_collection else obj.get_unidirectional_mappings()
-            return MappingDetailSerializer(mappings, many=True, context=context).data
+            return MappingDetailSerializer(mappings.order_by('id'), many=True, context=context).data
 
         return []
 
diff --git a/core/integration_tests/tests_concepts.py b/core/integration_tests/tests_concepts.py
index 87215f9c..0c943f14 100644
--- a/core/integration_tests/tests_concepts.py
+++ b/core/integration_tests/tests_concepts.py
@@ -4702,4 +4702,8 @@ def test_inverse_mappings_are_unchanged(self):
         batched = self.client.get(url).data
         with patch.object(ConceptAbstractSerializer, 'preload_page', lambda *args: None):
             per_concept = self.client.get(url).data
-        self.assertEqual(batched, per_concept)
+        # plain lists, so a failure shows the differing element
+        self.assertEqual(list(batched), list(per_concept))
+        for row in batched:
+            mapping_ids = [int(mapping['uuid']) for mapping in row['mappings']]
+            self.assertEqual(mapping_ids, sorted(mapping_ids))