diff --git a/src/applications/metamta/adapter/PhabricatorMailImplementationMailgunAdapter.php b/src/applications/metamta/adapter/PhabricatorMailImplementationMailgunAdapter.php
--- a/src/applications/metamta/adapter/PhabricatorMailImplementationMailgunAdapter.php
+++ b/src/applications/metamta/adapter/PhabricatorMailImplementationMailgunAdapter.php
@@ -52,6 +52,10 @@
     return $this;
   }
 
+  public function setSender($sender) {
+    $this->addHeader('List-Id', $sender);
+  }
+
   public function setBody($body) {
     $this->params['body'] = $body;
     return $this;
diff --git a/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerAdapter.php b/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerAdapter.php
--- a/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerAdapter.php
+++ b/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerAdapter.php
@@ -107,6 +107,11 @@
     return $this;
   }
 
+  public function setSender($sender) {
+    $this->addHeader('List-Id', $sender);
+    return $this;
+  }
+
   public function setSubject($subject) {
     $this->mailer->Subject = $subject;
     return $this;
diff --git a/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerLiteAdapter.php b/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerLiteAdapter.php
--- a/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerLiteAdapter.php
+++ b/src/applications/metamta/adapter/PhabricatorMailImplementationPHPMailerLiteAdapter.php
@@ -36,6 +36,11 @@
     return $this;
   }
 
+  public function setSender($sender) {
+    $this->mailer->Sender = $sender;
+    $this->mailer->AddCustomHeader('List-Id:'.$sender);
+  }
+
   public function addReplyTo($email, $name = '') {
     $this->mailer->AddReplyTo($email, $name);
     return $this;
diff --git a/src/applications/metamta/adapter/PhabricatorMailImplementationSendGridAdapter.php b/src/applications/metamta/adapter/PhabricatorMailImplementationSendGridAdapter.php
--- a/src/applications/metamta/adapter/PhabricatorMailImplementationSendGridAdapter.php
+++ b/src/applications/metamta/adapter/PhabricatorMailImplementationSendGridAdapter.php
@@ -51,6 +51,10 @@
     return $this;
   }
 
+  public function setSender($sender) {
+    $this->addHeader('List-Id', $sender);
+  }
+
   public function setBody($body) {
     $this->params['body'] = $body;
     return $this;
diff --git a/src/applications/metamta/adapter/PhabricatorMailImplementationTestAdapter.php b/src/applications/metamta/adapter/PhabricatorMailImplementationTestAdapter.php
--- a/src/applications/metamta/adapter/PhabricatorMailImplementationTestAdapter.php
+++ b/src/applications/metamta/adapter/PhabricatorMailImplementationTestAdapter.php
@@ -59,6 +59,10 @@
     return $this;
   }
 
+  public function setSender($sender) {
+    $this->addHeader('List-Id', $sender);
+  }
+
   public function setBody($body) {
     $this->guts['body'] = $body;
     return $this;
diff --git a/src/applications/metamta/storage/PhabricatorMetaMTAMail.php b/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
--- a/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
+++ b/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
@@ -503,6 +503,7 @@
 
             if ($can_send_as_user) {
               $mailer->setFrom($actor_email, $actor_name);
+              $mailer->setSender($default_from);
             } else {
               $from_email = coalesce($actor_email, $default_from);
               $from_name = coalesce($actor_name, pht('Phabricator'));