diff --git a/lisp/ob-tangle.el b/lisp/ob-tangle.el
index de9109450..88a6a5670 100644
--- a/lisp/ob-tangle.el
+++ b/lisp/ob-tangle.el
@@ -37,6 +37,7 @@
 (declare-function org-back-to-heading "org" (invisible-ok))
 (declare-function org-fill-template "org" (template alist))
 
+;;;###autoload
 (defcustom org-babel-tangle-lang-exts
   '(("emacs-lisp" . "el"))
   "Alist mapping languages to their file extensions.