diff --git a/contrib/rename-tags.lua b/contrib/rename-tags.lua
new file mode 100644
index 0000000..69c6e0a
--- /dev/null
+++ b/contrib/rename-tags.lua
@@ -0,0 +1,114 @@
+--[[
+Rename tags
+
+AUTHOR
+Sebastian Witt (se.witt@gmx.net)
+
+INSTALLATION
+* copy this file in $CONFIGDIR/lua/ where CONFIGDIR
+is your darktable configuration directory
+* add the following line in the file $CONFIGDIR/luarc
+  require "rename-tags"
+
+USAGE
+* In lighttable there is a new entry: 'rename tag'
+* Enter old tag (this one gets deleted!)
+* Enter new tag name
+
+LICENSE
+GPLv2
+
+]]
+
+local darktable = require "darktable"
+local debug = require "darktable.debug"
+
+-- GUI entries
+local old_tag = darktable.new_widget("entry") { tooltip = "Enter old tag" }
+local new_tag = darktable.new_widget("entry") { tooltip = "Enter new tag" }
+
+-- This function does the renaming
+local function rename_tags(widget)
+  -- If entries are empty, return
+  if old_tag.text == '' then
+    darktable.print ("Old tag can't be empty")
+    return
+  end
+  if new_tag.text == '' then
+    darktable.print ("New tag can't be empty")
+    return
+  end
+  
+  local Count = 0
+
+  -- Check if old tag exists
+  local ot = darktable.tags.find (old_tag.text)
+  
+  if not ot then
+    darktable.print ("Old tag does not exist")
+    return
+  end
+
+  -- Show job
+  local job = darktable.gui.create_job ("Renaming tag", true)
+  
+  old_tag.editable = false
+  new_tag.editable = false
+
+  -- Create if it does not exists
+  local nt = darktable.tags.create (new_tag.text)
+
+  -- Search images for old tag
+  dbcount = #darktable.database
+  for i,image in ipairs(darktable.database) do
+    -- Update progress bar
+    job.percent = i / dbcount
+    
+    local tags = image:get_tags ()
+    for _,t in ipairs (tags) do
+      if t.name == old_tag.text then
+        -- Found it, attach new tag
+        image:attach_tag (nt)
+        Count = Count + 1
+      end
+    end
+  end
+
+  -- Delete old tag, this removes it from all images
+  darktable.tags.delete (ot)
+
+  job.valid = false
+  darktable.print ("Renamed tags for " .. Count .. " images")
+  old_tag.editable = true
+  new_tag.editable = true
+end
+
+-- GUI
+local old_widget = darktable.new_widget ("box") {
+    orientation = "horizontal",
+    darktable.new_widget("label") { label = "Old tag" },
+    old_tag
+}
+
+local new_widget = darktable.new_widget ("box") {
+    orientation = "horizontal",
+    darktable.new_widget("label") { label = "New tag" },
+    new_tag
+}
+
+local function rename_reset(widget)
+    old_tag.text = ''
+    new_tag.text = ''
+end
+
+local rename_widget = darktable.new_widget ("box") {
+    orientation = "vertical",
+    reset_callback = rename_reset,
+    old_widget,
+    new_widget,
+    darktable.new_widget("button") { label = "Go", clicked_callback = rename_tags }
+}
+
+
+darktable.register_lib ("rename_tags", "rename tag", true, true, {[darktable.gui.views.lighttable] = {"DT_UI_CONTAINER_PANEL_RIGHT_CENTER", 20},}, rename_widget, nil, nil)
+