diff --git a/overlay.nix b/overlay.nix
index 91ed64b..a560c36 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -25,6 +25,7 @@ customPlugins: self: super: {
 
           if has("autocmd")
             au BufReadPost *.rkt,*.rktl set filetype=racket
+            au BufReadPost *.lidr set filetype=idris
             au filetype racket set lisp
             au filetype racket set autoindent
           endif