diff --git a/src/applications/feed/PhabricatorFeedStoryPublisher.php b/src/applications/feed/PhabricatorFeedStoryPublisher.php
--- a/src/applications/feed/PhabricatorFeedStoryPublisher.php
+++ b/src/applications/feed/PhabricatorFeedStoryPublisher.php
@@ -12,6 +12,7 @@
   private $mailRecipientPHIDs = array();
   private $notifyAuthor;
   private $mailTags = array();
+  private $unexpandablePHIDs = array();
 
   public function setMailTags(array $mail_tags) {
     $this->mailTags = $mail_tags;
@@ -46,6 +47,15 @@
     return $this;
   }
 
+  public function setUnexpandablePHIDs(array $unexpandable_phids) {
+    $this->unexpandablePHIDs = $unexpandable_phids;
+    return $this;
+  }
+
+  public function getUnexpandablePHIDs() {
+    return $this->unexpandablePHIDs;
+  }
+
   public function setStoryType($story_type) {
     $this->storyType = $story_type;
     return $this;
@@ -254,10 +264,36 @@
   }
 
   private function expandRecipients(array $phids) {
-    return id(new PhabricatorMetaMTAMemberQuery())
+    $expanded_phids = id(new PhabricatorMetaMTAMemberQuery())
       ->setViewer(PhabricatorUser::getOmnipotentUser())
       ->withPHIDs($phids)
       ->executeExpansion();
+
+    // Filter out unexpandable PHIDs from the results. The typical case for
+    // this is that resigned reviewers should not be notified just because
+    // they are a member of some project or package reviewer.
+
+    $original_map = array_fuse($phids);
+    $unexpandable_map = array_fuse($this->unexpandablePHIDs);
+
+    foreach ($expanded_phids as $key => $phid) {
+      // We can keep this expanded PHID if it was present originally.
+      if (isset($original_map[$phid])) {
+        continue;
+      }
+
+      // We can also keep it if it isn't marked as unexpandable.
+      if (!isset($unexpandable_map[$phid])) {
+        continue;
+      }
+
+      // If it's unexpandable and we produced it by expanding recipients,
+      // throw it away.
+      unset($expanded_phids[$key]);
+    }
+    $expanded_phids = array_values($expanded_phids);
+
+    return $expanded_phids;
   }
 
   /**
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
@@ -3199,6 +3199,11 @@
     $story_type = $this->getFeedStoryType();
     $story_data = $this->getFeedStoryData($object, $xactions);
 
+    $unexpandable_phids = $this->mailUnexpandablePHIDs;
+    if (!is_array($unexpandable_phids)) {
+      $unexpandable_phids = array();
+    }
+
     id(new PhabricatorFeedStoryPublisher())
       ->setStoryType($story_type)
       ->setStoryData($story_data)
@@ -3207,6 +3212,7 @@
       ->setRelatedPHIDs($related_phids)
       ->setPrimaryObjectPHID($object->getPHID())
       ->setSubscribedPHIDs($subscribed_phids)
+      ->setUnexpandablePHIDs($unexpandable_phids)
       ->setMailRecipientPHIDs($mailed_phids)
       ->setMailTags($this->getMailTags($object, $xactions))
       ->publish();