diff --git a/modules/services/mail/dovecot2.nix b/modules/services/mail/dovecot2.nix
index c1f21ba457f..fc97e0d3ad0 100644
--- a/modules/services/mail/dovecot2.nix
+++ b/modules/services/mail/dovecot2.nix
@@ -43,7 +43,7 @@ let
       }
 
       pop3_uidl_format = %08Xv%08Xu
-    '';
+    '' + cfg.extraConfig;
 
   confFile = pkgs.writeText "dovecot.conf" dovecotConf;
 
@@ -72,6 +72,12 @@ in
         description = "Dovecot group name.";
       };
 
+      extraConfig = mkOption {
+        default = "";
+        example = "mail_debug = yes";
+        description = "Additional entries to put verbatim into Dovecot's config file.";
+      };
+
       mailLocation = mkOption {
         default = "maildir:/var/spool/mail/%u"; /* Same as inbox, as postfix */
         example = "maildir:~/mail:INBOX=/var/spool/mail/%u";