diff --git a/disco/api/client.py b/disco/api/client.py
index 04214b3..0aae49e 100644
--- a/disco/api/client.py
+++ b/disco/api/client.py
@@ -376,6 +376,7 @@ class APIClient(LoggingClass):
     def guilds_bans_create(self, guild, user, delete_message_days=0, reason=None):
         self.http(Routes.GUILDS_BANS_CREATE, dict(guild=guild, user=user), params={
             'delete-message-days': delete_message_days,
+            'reason': reason,
         }, headers=_reason_header(reason))
 
     def guilds_bans_delete(self, guild, user, reason=None):