diff --git a/THEMES.md b/THEMES.md
index 2cc3a9c..917b517 100644
--- a/THEMES.md
+++ b/THEMES.md
@@ -40,8 +40,11 @@ it'll try it's best to generate one.
 </p>
 
 ### ayu
-It's a combination of ayu_light, ayu_dark & ayu_mirage. It loads one of these
-them based you your `g:ayucolor` option.
+It's a combination of ayu_light, ayu_dark & ayu_mirage. If `g:ayucolor` exists,
+it loads one of these based on your `g:ayucolor` option. Otherwise, it will
+load ayu_light when background=light and ayu_dark when background=dark
+But if `g:ayuprefermirage` exists, it will load ayu_mirage instead when
+`background=dark`.
 
 ### codedark
 <p>
diff --git a/lua/lualine/themes/ayu.lua b/lua/lualine/themes/ayu.lua
index 380e3a4..b784306 100644
--- a/lua/lualine/themes/ayu.lua
+++ b/lua/lualine/themes/ayu.lua
@@ -2,6 +2,7 @@
 -- MIT license, see LICENSE for more details.
 -- Credit: itchyny(lightline)
 -- License: MIT License
-local style = vim.g.ayucolor or 'dark'
+local background = vim.opt.background:get()
+local style = vim.g.ayucolor or ((background == 'dark') and vim.g.ayuprefermirage and 'mirage' or background)
 
 return require('lualine.themes.ayu_' .. style)