diff --git a/src/applications/calendar/editor/PhabricatorCalendarEventEditor.php b/src/applications/calendar/editor/PhabricatorCalendarEventEditor.php
--- a/src/applications/calendar/editor/PhabricatorCalendarEventEditor.php
+++ b/src/applications/calendar/editor/PhabricatorCalendarEventEditor.php
@@ -200,6 +200,11 @@
   protected function shouldPublishFeedStory(
     PhabricatorLiskDAO $object,
     array $xactions) {
+
+    if ($object->isImportedEvent()) {
+      return false;
+    }
+
     return true;
   }
 
@@ -210,6 +215,11 @@
   protected function shouldSendMail(
     PhabricatorLiskDAO $object,
     array $xactions) {
+
+    if ($object->isImportedEvent()) {
+      return false;
+    }
+
     return true;
   }