diff --git a/src/documents/serialisers.py b/src/documents/serialisers.py
index c2b2ae7fd..db50d34ba 100644
--- a/src/documents/serialisers.py
+++ b/src/documents/serialisers.py
@@ -37,7 +37,8 @@ class DocumentSerializer(serializers.ModelSerializer):
             "created",
             "modified",
             "file_name",
-            "download_url"
+            "download_url",
+            "thumbnail_url",
         )