diff --git a/plugin/fugitive.vim b/plugin/fugitive.vim
index 75cfe20..5cf1ae1 100644
--- a/plugin/fugitive.vim
+++ b/plugin/fugitive.vim
@@ -1176,13 +1176,15 @@ function! s:Merge(cmd, bang, args) abort
           \  !empty(s:repo().git_chomp('diff-files', '--diff-filter=U')))
       let &l:makeprg = g:fugitive_git_executable.' diff-files --name-status --diff-filter=U'
     else
-      let &l:makeprg = s:sub(g:fugitive_git_executable.' -c core.editor=false '.
-            \ a:cmd . (a:args =~# ' \%(--no-edit\|--abort\|-m\)\>' ? '' : ' --edit') . ' ' . a:args,
-            \ ' *$', '')
+      let &l:makeprg = s:sub(g:fugitive_git_executable . ' ' . a:cmd .
+            \ (a:args =~# ' \%(--no-edit\|--abort\|-m\)\>' ? '' : ' --edit') .
+            \ ' ' . a:args, ' *$', '')
     endif
-    if !empty($GIT_EDITOR)
+    if !empty($GIT_EDITOR) || has('win32')
       let old_editor = $GIT_EDITOR
       let $GIT_EDITOR = 'false'
+    else
+      let &l:makeprg = 'env GIT_EDITOR=false ' . &l:makeprg
     endif
     execute cd fnameescape(s:repo().tree())
     silent noautocmd make!