diff --git a/default.nix b/default.nix
index 6361c47..fdfaee3 100644
--- a/default.nix
+++ b/default.nix
@@ -574,6 +574,14 @@ in
       '';
     };
 
+    useUTF8FolderNames = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Store mailbox names on disk using UTF-8 instead of modified UTF-7 (mUTF-7).
+      '';
+    };
+
     hierarchySeparator = mkOption {
       type = types.str;
       default = ".";
diff --git a/mail-server/dovecot.nix b/mail-server/dovecot.nix
index 771dedd..7d73ee2 100644
--- a/mail-server/dovecot.nix
+++ b/mail-server/dovecot.nix
@@ -29,10 +29,11 @@ let
   bool2int = x: if x then "1" else "0";
 
   maildirLayoutAppendix = lib.optionalString cfg.useFsLayout ":LAYOUT=fs";
+  maildirUTF8FolderNames = lib.optionalString cfg.useUTF8FolderNames ":UTF-8";
 
   # maildir in format "/${domain}/${user}"
   dovecotMaildir =
-    "maildir:${cfg.mailDirectory}/%d/%n${maildirLayoutAppendix}"
+    "maildir:${cfg.mailDirectory}/%d/%n${maildirLayoutAppendix}${maildirUTF8FolderNames}"
     + (lib.optionalString (cfg.indexDir != null)
        ":INDEX=${cfg.indexDir}/%d/%n"
       );