diff --git a/runtime/spell/fixdup.vim b/runtime/spell/fixdup.vim
new file mode 100644
index 0000000..0dd532d
--- /dev/null
+++ b/runtime/spell/fixdup.vim
@@ -0,0 +1,27 @@
+" Vim script to fix duplicate words in a .dic file  vim: set ft=vim:
+"
+" Usage: Edit the .dic file and source this script.
+
+let deleted = 0
+
+" Start below the word count.
+let lnum = 2
+while lnum <= line('$')
+  let word = getline(lnum)
+  if word !~ '/'
+    if search('^' . word . '/', 'w') != 0
+      let deleted += 1
+      exe lnum . "d"
+      continue		" don't increment lnum, it's already at the next word
+    endif
+  endif
+  let lnum += 1
+endwhile
+
+if deleted == 0
+  echomsg "No duplicate words found"
+elseif deleted == 1
+  echomsg "Deleted 1 duplicate word"
+else
+  echomsg printf("Deleted %d duplicate words", deleted)
+endif