diff --git a/data/api/client-server/joining.yaml b/data/api/client-server/joining.yaml
index e88c9e43..1019abbd 100644
--- a/data/api/client-server/joining.yaml
+++ b/data/api/client-server/joining.yaml
@@ -117,7 +117,7 @@ paths:
       description: |-
         *Note that this API takes either a room ID or alias, unlike* `/rooms/{roomId}/join`.
 
-        This API starts a user'S participation in a particular room, if that user
+        This API starts a user's participation in a particular room, if that user
         is allowed to participate in that room. After this call, the client is
         allowed to see all current state events in the room, and all subsequent
         events associated with the room until the user leaves the room.