diff --git a/guix/ui.scm b/guix/ui.scm
index ad78d5cedd..e918b5b64f 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -2066,8 +2066,10 @@ contain a 'define-command' form."
 (define (extension-directories)
   "Return the list of directories containing Guix extensions."
   (filter file-exists?
-          (parse-path
-           (getenv "GUIX_EXTENSIONS_PATH"))))
+          (map (cut string-append <> "/extensions")
+               (parse-path
+                (string-append (config-directory) ":"
+                 (getenv "GUIX_EXTENSIONS_PATH"))))))
 
 (define (commands)
   "Return the list of commands, alphabetically sorted."