diff --git a/openapi/components/responses/userGroupMembership-list.yaml b/openapi/components/responses/userGroupMembership-list.yaml
index bed05f75..630bbb23 100644
--- a/openapi/components/responses/userGroupMembership-list.yaml
+++ b/openapi/components/responses/userGroupMembership-list.yaml
@@ -7,6 +7,8 @@ content:
         A group within Schoolbox.
         
         This contains some of the folder's fields in this context.
-      type: object
-      properties:
-        $ref: ../schemas/userGroupMembership-readableFields.yaml
+      type: array
+      items:
+        type: object
+        properties:
+          $ref: ../schemas/userGroupMembership-readableFields.yaml
diff --git a/openapi/components/schemas/user-readableFields.yaml b/openapi/components/schemas/user-readableFields.yaml
index 2495b746..472ae35e 100644
--- a/openapi/components/schemas/user-readableFields.yaml
+++ b/openapi/components/schemas/user-readableFields.yaml
@@ -16,15 +16,15 @@ properties:
   
   groups:
     description: |
-      This user's group memberships indexed by folder ID of the groups.
-    type: object
-    additionalProperties:
+      This user's group memberships
+    type: array
+    items:
+      type: object
       title: Group Membership
       description: |
         A group within Schoolbox.
         
         This contains some of the folder's fields in this context.
-      type: object
       properties:
         $ref: ../schemas/userGroupMembership-readableFields.yaml