diff --git a/config/initializers/doorkeeper.rb b/config/initializers/doorkeeper.rb
index b11b32dea..2a2355c6d 100644
--- a/config/initializers/doorkeeper.rb
+++ b/config/initializers/doorkeeper.rb
@@ -361,7 +361,7 @@ Doorkeeper.configure do
   #   https://datatracker.ietf.org/doc/html/rfc6819#section-4.4.3
   #
   #
-  grant_flows %w[authorization_code client_credentials password]
+  grant_flows %w[authorization_code client_credentials password refresh_token]
 
   # Allows to customize OAuth grant flows that +each+ application support.
   # You can configure a custom block (or use a class respond to `#call`) that must