diff --git a/autoload/tagbar/prototypes/basetag.vim b/autoload/tagbar/prototypes/basetag.vim
index 2f411bf..d002afa 100644
--- a/autoload/tagbar/prototypes/basetag.vim
+++ b/autoload/tagbar/prototypes/basetag.vim
@@ -3,7 +3,7 @@ let s:visibility_symbols = {
     \ 'protected' : '#',
     \ 'private'   : '-'
 \ }
-if !empty(g:tagbar_visibility_symbols)
+if exists('g:tagbar_visibility_symbols') && !empty(g:tagbar_visibility_symbols)
     let s:visibility_symbols = g:tagbar_visibility_symbols
 endif