diff --git a/.emacs.d/lisp/init-lisp.el b/.emacs.d/lisp/init-lisp.el
index 7665fa0d..627b7e75 100644
--- a/.emacs.d/lisp/init-lisp.el
+++ b/.emacs.d/lisp/init-lisp.el
@@ -26,6 +26,10 @@
          (pop-to-buffer (slime-output-buffer))))))
 
 (with-eval-after-load 'slime
+  ;; REVIEW: Fix issue https://github.com/slime/slime/issues/523:
+  (setq slime-defpackage-regexp
+        "^(\\(cl:\\|common-lisp:\\|uiop:\\)?\\(defpackage\\|define-package\\)\\>[ \t']*")
+
   (setq slime-lisp-implementations
         '((sbcl ("sbcl" "--noinform"))
           (ccl ("ccl"))