diff --git a/docs/asgi.rst b/docs/asgi.rst
index 54d82f3..234b359 100644
--- a/docs/asgi.rst
+++ b/docs/asgi.rst
@@ -527,7 +527,9 @@ Keys:
   and UTF8 byte sequences decoded into characters.
 
 * ``query_string``: Unicode string URL portion after the ``?``, already
-  url-decoded, like ``path``. Optional, default is ``""``.
+  url-decoded, like ``path``. Optional, default is ``""``. ``+`` characters in
+  this portion should be interpreted by the application to be literal pluses,
+  not spaces.
 
 * ``root_path``: Unicode string that indicates the root path this application
   is mounted at; same as ``SCRIPT_NAME`` in WSGI. Optional, defaults