diff --git a/CHANGELOG.md b/CHANGELOG.md
index 632e2a58..bba27d96 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 ### Bugs fixed
 
+* [#550](https://github.com/clojure-emacs/clojure-mode/issues/550): Fix `outline-regexp` so `outline-insert-heading` behaves correctly.
 * [#551](https://github.com/clojure-emacs/clojure-mode/issues/551): Indent `clojure-align` region before aligning.
 * [#520](https://github.com/clojure-emacs/clojure-mode/issues/508): Fix allow `clojure-align-cond-forms` to recognize qualified forms.
 * Enhance add arity refactoring to support a `defn` inside a reader conditional.
diff --git a/clojure-mode.el b/clojure-mode.el
index 634be9cb..3d7e0be0 100644
--- a/clojure-mode.el
+++ b/clojure-mode.el
@@ -507,7 +507,7 @@ replacement for `cljr-expand-let`."
   (add-to-list 'imenu-generic-expression '(nil clojure-match-next-def 0))
   (setq-local indent-tabs-mode nil)
   (setq-local paragraph-ignore-fill-prefix t)
-  (setq-local outline-regexp ";;;\\(;* [^ \t\n]\\)\\|(")
+  (setq-local outline-regexp ";;;;* ")
   (setq-local outline-level 'lisp-outline-level)
   (setq-local comment-start ";")
   (setq-local comment-start-skip ";+ *")