diff --git a/hgext/mq.py b/hgext/mq.py
--- a/hgext/mq.py
+++ b/hgext/mq.py
@@ -2504,7 +2504,7 @@ def strip(ui, repo, *revs, **opts):
     backup = 'all'
     if opts.get('backup'):
         backup = 'strip'
-    elif opts.get('no-backup') or opts.get('nobackup'):
+    elif opts.get('no_backup') or opts.get('nobackup'):
         backup = 'none'
 
     cl = repo.changelog