diff --git a/ftdetect/xonsh.vim b/ftdetect/xonsh.vim
index b542b3a..9b2b4bc 100644
--- a/ftdetect/xonsh.vim
+++ b/ftdetect/xonsh.vim
@@ -1,2 +1,3 @@
 au BufNewFile,BufRead .xonshrc set filetype=xonsh
 au BufNewFile,BufRead *.xsh set filetype=xonsh
+au FileType xonsh setlocal commentstring=#\ %s