diff --git a/elisp/org-mu4e-compose.el b/elisp/org-mu4e-compose.el
index 124f1bb..1922992 100644
--- a/elisp/org-mu4e-compose.el
+++ b/elisp/org-mu4e-compose.el
@@ -15,7 +15,8 @@
 
 (defgroup org-mu4e nil
   "Edit mu4e messages with `org-mode'."
-  :prefix "org-mu4e-")
+  :prefix "org-mu4e-"
+  :group 'mail)
 
 (defcustom org-mu4e-preview-html-images t
   "If non-nil, render images in rendered HTML preview buffers.