diff --git a/tools/vim/lammps.vim b/tools/vim/lammps.vim
index a34fa53cbc..d8fc58a2fc 100644
--- a/tools/vim/lammps.vim
+++ b/tools/vim/lammps.vim
@@ -62,3 +62,4 @@ if !exists("did_lammps_syntax_inits")
 endif
 
 let b:current_syntax = "lammps"
+vim: set expandtab