--- a/sites/all/modules/amazon_ses/amazon_ses.mail.inc
+++ b/sites/all/modules/amazon_ses/amazon_ses.mail.inc
@@ -44,12 +44,19 @@
     );

     $opt['ReturnPath'] = $source;
+
+    // Reply-to headers
     if (isset($message['headers']['Reply-To']) && !empty($message['headers']['Reply-To'])) {
-      if (strpos($message['headers']['Reply-To'], '<')) {
-        $opt['ReturnPath'] = preg_replace('/>.*/', '', preg_replace('/.*</', '', $message['headers']['Reply-To']));
-      }
-      else {
-        $opt['ReturnPath'] = $message['headers']['Reply-To'];
+      $reply_to_members = split(",", $message['headers']['Reply-To']);
+      $n = 1;
+      foreach ($reply_to_members as $member) {
+        if (strpos($member, '<')) {
+          $opt['ReplyToAddresses.member.' . $n] = preg_replace('/>.*/', '', preg_replace('/.*</', '', $member));
+        }
+        else {
+         $opt['ReplyToAddresses.member.' . $n] = $member;
+        }
+        $n++;
       }
     }