diff --git a/vimrc b/vimrc
index dc2ae85..123c54a 100644
--- a/vimrc
+++ b/vimrc
@@ -189,6 +189,7 @@ call tcomment#type#Define('chaskell', '-- %s')
 call tcomment#type#Define('vala', '// %s')
 call tcomment#type#Define('tptp', '%% %s')
 call tcomment#type#Define('lean', '-- %s')
+call tcomment#type#Define('lean3', '-- %s')
 
 au syntax tex setl iskeyword+=:
 au syntax tex syn region texZone start="\\begin{clilisting}" end="\\end{clilisting}\|%stopzone\>"