diff --git a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
--- a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
+++ b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
@@ -3084,6 +3084,11 @@
             ->withObjectPHIDs(array($object->getPHID()))
             ->withPHIDs($xaction_phids)
             ->execute();
+
+          // Sort the mail transactions in the input order.
+          $mail_xactions = mpull($mail_xactions, null, 'getPHID');
+          $mail_xactions = array_select_keys($mail_xactions, $xaction_phids);
+          $mail_xactions = array_values($mail_xactions);
         } else {
           $mail_xactions = array();
         }