diff --git a/autoload/do.vim b/autoload/do.vim
index 25900e2..380c5d2 100644
--- a/autoload/do.vim
+++ b/autoload/do.vim
@@ -54,3 +54,17 @@ function! do#cursor_highlight_groups()
   let l:lo = synIDattr(synIDtrans(synID(line('.'),col('.'),1)),'name')
   echo 'hi<'.l:hi.'> trans<'.l:trans.'> lo<'.l:lo.'>'
 endfunction
+
+" Rename C/C++ include guard
+function! do#rename_include_guard(old)
+  " Prompt for new guard name
+  let l:new = input('Rename include guard: ', a:old)
+  " Set a mark to jump back to
+  normal mr
+  " Replace the old guard name with the new one
+  exec '%s/\(#ifndef\|#define\|#endif\s\+\/\/\)\s\+\zs'.a:old.'/'.l:new.'/g'
+  " Stop highlighting search results
+  nohlsearch
+  " Jump back to the set mark
+  normal 'r
+endfunction
diff --git a/plugin/mappings.vim b/plugin/mappings.vim
index 1a7e1ae..e1c75bd 100644
--- a/plugin/mappings.vim
+++ b/plugin/mappings.vim
@@ -91,3 +91,6 @@ nnoremap <leader><CR> :ToggleCheckbox<CR>
 
 " Show highlight groups under the cursor
 nnoremap <leader>hi :CursorHighlightGroups<CR>
+
+" Rename C/C++ include guard
+nnoremap <leader>rg :call do#rename_include_guard(expand('<cword>'))<cr>