diff --git a/changelog.d/18874.misc b/changelog.d/18874.misc
new file mode 100644
index 0000000000..729befb5e8
--- /dev/null
+++ b/changelog.d/18874.misc
@@ -0,0 +1 @@
+Use the `Enum`'s value for the dictionary key when responding to an admin request for experimental features.
diff --git a/synapse/rest/admin/experimental_features.py b/synapse/rest/admin/experimental_features.py
index afb71f4a0f..3d3015cef7 100644
--- a/synapse/rest/admin/experimental_features.py
+++ b/synapse/rest/admin/experimental_features.py
@@ -92,9 +92,9 @@ class ExperimentalFeaturesRestServlet(RestServlet):
         user_features = {}
         for feature in ExperimentalFeature:
             if feature in enabled_features:
-                user_features[feature] = True
+                user_features[feature.value] = True
             else:
-                user_features[feature] = False
+                user_features[feature.value] = False
         return HTTPStatus.OK, {"features": user_features}
 
     async def on_PUT(