diff --git a/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php b/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php
--- a/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php
+++ b/src/applications/calendar/controller/PhabricatorCalendarEventEditController.php
@@ -105,15 +105,7 @@
       $subscribers = PhabricatorSubscribersQuery::loadSubscribersForPHID(
         $event->getPHID());
 
-      $invitees = array();
-      foreach ($event->getInvitees() as $invitee) {
-        if ($invitee->isUninvited()) {
-          continue;
-        } else {
-          $invitees[] = $invitee->getInviteePHID();
-        }
-      }
-
+      $invitees = $event->getInviteePHIDsForEdit();
       $cancel_uri = $event->getURI();
     }
 
@@ -172,14 +164,6 @@
       $icon = $request->getStr('icon');
 
       $invitees = $request->getArr('invitees');
-      $new_invitees = $this->getNewInviteeList($invitees, $event);
-      $status_attending = PhabricatorCalendarEventInvitee::STATUS_ATTENDING;
-      if ($this->isCreate()) {
-        $status = idx($new_invitees, $viewer->getPHID());
-        if ($status) {
-          $new_invitees[$viewer->getPHID()] = $status_attending;
-        }
-      }
 
       $xactions[] = id(new PhabricatorCalendarEventTransaction())
         ->setTransactionType(
@@ -236,7 +220,7 @@
       $xactions[] = id(new PhabricatorCalendarEventTransaction())
         ->setTransactionType(
           PhabricatorCalendarEventTransaction::TYPE_INVITE)
-        ->setNewValue($new_invitees);
+        ->setNewValue($invitees);
 
       $xactions[] = id(new PhabricatorCalendarEventTransaction())
         ->setTransactionType(
@@ -487,7 +471,6 @@
       ->setUser($viewer)
       ->setDatasource(new PhabricatorMetaMTAMailableDatasource());
 
-
     $icon = id(new PHUIFormIconSetControl())
       ->setLabel(pht('Icon'))
       ->setName('icon')
@@ -574,32 +557,6 @@
   }
 
 
-  public function getNewInviteeList(array $phids, $event) {
-    $invitees = $event->getInvitees();
-    $invitees = mpull($invitees, null, 'getInviteePHID');
-    $invited_status = PhabricatorCalendarEventInvitee::STATUS_INVITED;
-    $uninvited_status = PhabricatorCalendarEventInvitee::STATUS_UNINVITED;
-    $phids = array_fuse($phids);
-
-    $new = array();
-    foreach ($phids as $phid) {
-      $old_status = $event->getUserInviteStatus($phid);
-      if ($old_status != $uninvited_status) {
-        continue;
-      }
-      $new[$phid] = $invited_status;
-    }
-
-    foreach ($invitees as $invitee) {
-      $deleted_invitee = !idx($phids, $invitee->getInviteePHID());
-      if ($deleted_invitee) {
-        $new[$invitee->getInviteePHID()] = $uninvited_status;
-      }
-    }
-
-    return $new;
-  }
-
   private function getDefaultTimeValues($viewer) {
     $start = new DateTime('@'.time());
     $start->setTimeZone($viewer->getTimeZone());
diff --git a/src/applications/calendar/editor/PhabricatorCalendarEditEngine.php b/src/applications/calendar/editor/PhabricatorCalendarEditEngine.php
--- a/src/applications/calendar/editor/PhabricatorCalendarEditEngine.php
+++ b/src/applications/calendar/editor/PhabricatorCalendarEditEngine.php
@@ -60,6 +60,14 @@
   }
 
   protected function buildCustomEditFields($object) {
+    $viewer = $this->getViewer();
+
+    if ($this->getIsCreate()) {
+      $invitee_phids = array($viewer->getPHID());
+    } else {
+      $invitee_phids = $object->getInviteePHIDsForEdit();
+    }
+
     $fields = array(
       id(new PhabricatorTextEditField())
         ->setKey('name')
@@ -90,6 +98,17 @@
         ->setConduitDescription(pht('Cancel or restore the event.'))
         ->setConduitTypeDescription(pht('True to cancel the event.'))
         ->setValue($object->getIsCancelled()),
+      id(new PhabricatorDatasourceEditField())
+        ->setKey('inviteePHIDs')
+        ->setAliases(array('invite', 'invitee', 'invitees', 'inviteePHID'))
+        ->setLabel(pht('Invitees'))
+        ->setDatasource(new PhabricatorMetaMTAMailableDatasource())
+        ->setTransactionType(PhabricatorCalendarEventTransaction::TYPE_INVITE)
+        ->setDescription(pht('Users invited to the event.'))
+        ->setConduitDescription(pht('Change invited users.'))
+        ->setConduitTypeDescription(pht('New event invitees.'))
+        ->setValue($invitee_phids)
+        ->setCommentActionLabel(pht('Change Invitees')),
       id(new PhabricatorIconSetEditField())
         ->setKey('icon')
         ->setLabel(pht('Icon'))
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
@@ -109,20 +109,8 @@
         $actor_phid = $this->getActingAsPHID();
         return $object->getUserInviteStatus($actor_phid);
       case PhabricatorCalendarEventTransaction::TYPE_INVITE:
-        $map = $xaction->getNewValue();
-        $phids = array_keys($map);
-        $invitees = mpull($object->getInvitees(), null, 'getInviteePHID');
-
-        $old = array();
-        foreach ($phids as $phid) {
-          $invitee = idx($invitees, $phid);
-          if ($invitee) {
-            $old[$phid] = $invitee->getStatus();
-          } else {
-            $old[$phid] = PhabricatorCalendarEventInvitee::STATUS_UNINVITED;
-          }
-        }
-        return $old;
+        $invitees = $object->getInvitees();
+        return mpull($invitees, 'getStatus', 'getInviteePHID');
     }
 
     return parent::getCustomTransactionOldValue($object, $xaction);
@@ -137,7 +125,6 @@
       case PhabricatorCalendarEventTransaction::TYPE_NAME:
       case PhabricatorCalendarEventTransaction::TYPE_DESCRIPTION:
       case PhabricatorCalendarEventTransaction::TYPE_CANCEL:
-      case PhabricatorCalendarEventTransaction::TYPE_INVITE:
       case PhabricatorCalendarEventTransaction::TYPE_ICON:
         return $xaction->getNewValue();
       case PhabricatorCalendarEventTransaction::TYPE_ACCEPT:
@@ -150,6 +137,45 @@
       case PhabricatorCalendarEventTransaction::TYPE_START_DATE:
       case PhabricatorCalendarEventTransaction::TYPE_END_DATE:
         return $xaction->getNewValue();
+      case PhabricatorCalendarEventTransaction::TYPE_INVITE:
+        $status_invited = PhabricatorCalendarEventInvitee::STATUS_INVITED;
+        $status_uninvited = PhabricatorCalendarEventInvitee::STATUS_UNINVITED;
+        $status_attending = PhabricatorCalendarEventInvitee::STATUS_ATTENDING;
+
+        $invitees = $object->getInvitees();
+        foreach ($invitees as $key => $invitee) {
+          if ($invitee->getStatus() == $status_uninvited) {
+            unset($invitees[$key]);
+          }
+        }
+        $invitees = mpull($invitees, null, 'getInviteePHID');
+
+        $new = $xaction->getNewValue();
+        $new = array_fuse($new);
+
+        $all = array_keys($invitees + $new);
+        $map = array();
+        foreach ($all as $phid) {
+          $is_old = isset($invitees[$phid]);
+          $is_new = isset($new[$phid]);
+
+          if ($is_old && !$is_new) {
+            $map[$phid] = $status_uninvited;
+          } else if (!$is_old && $is_new) {
+            $map[$phid] = $status_invited;
+          }
+        }
+
+        // If we're creating this event and the actor is inviting themselves,
+        // mark them as attending.
+        if ($this->getIsNewObject()) {
+          $acting_phid = $this->getActingAsPHID();
+          if (isset($map[$acting_phid])) {
+            $map[$acting_phid] = $status_attending;
+          }
+        }
+
+        return $map;
     }
 
     return parent::getCustomTransactionNewValue($object, $xaction);
@@ -400,6 +426,40 @@
           $errors[] = $error;
         }
         break;
+      case PhabricatorCalendarEventTransaction::TYPE_INVITE:
+        $old = $object->getInvitees();
+        $old = mpull($old, null, 'getInviteePHID');
+        foreach ($xactions as $xaction) {
+          $new = $xaction->getNewValue();
+          $new = array_fuse($new);
+          $add = array_diff_key($new, $old);
+          if (!$add) {
+            continue;
+          }
+
+          // In the UI, we only allow you to invite mailable objects, but there
+          // is no definitive marker for "invitable object" today. Just allow
+          // any valid object to be invited.
+          $objects = id(new PhabricatorObjectQuery())
+            ->setViewer($this->getActor())
+            ->withPHIDs($add)
+            ->execute();
+          $objects = mpull($objects, null, 'getPHID');
+          foreach ($add as $phid) {
+            if (isset($objects[$phid])) {
+              continue;
+            }
+
+            $errors[] = new PhabricatorApplicationTransactionValidationError(
+              $type,
+              pht('Invalid'),
+              pht(
+                'Invitee "%s" identifies an object that does not exist or '.
+                'which you do not have permission to view.',
+                $phid));
+          }
+        }
+        break;
     }
 
     return $errors;
diff --git a/src/applications/calendar/storage/PhabricatorCalendarEvent.php b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
--- a/src/applications/calendar/storage/PhabricatorCalendarEvent.php
+++ b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
@@ -329,6 +329,19 @@
     return $this;
   }
 
+  public function getInviteePHIDsForEdit() {
+    $invitees = array();
+
+    foreach ($this->getInvitees() as $invitee) {
+      if ($invitee->isUninvited()) {
+        continue;
+      }
+      $invitees[] = $invitee->getInviteePHID();
+    }
+
+    return $invitees;
+  }
+
   public function getUserInviteStatus($phid) {
     $invitees = $this->getInvitees();
     $invitees = mpull($invitees, null, 'getInviteePHID');
diff --git a/src/applications/calendar/storage/PhabricatorCalendarEventTransaction.php b/src/applications/calendar/storage/PhabricatorCalendarEventTransaction.php
--- a/src/applications/calendar/storage/PhabricatorCalendarEventTransaction.php
+++ b/src/applications/calendar/storage/PhabricatorCalendarEventTransaction.php
@@ -18,7 +18,6 @@
   const TYPE_FREQUENCY = 'calendar.frequency';
   const TYPE_RECURRENCE_END_DATE = 'calendar.recurrenceenddate';
 
-
   const MAILTAG_RESCHEDULE = 'calendar-reschedule';
   const MAILTAG_CONTENT = 'calendar-content';
   const MAILTAG_OTHER = 'calendar-other';
@@ -177,6 +176,11 @@
       case self::TYPE_INVITE:
         $text = null;
 
+        // Fill in any new invitees as "uninvited" in the old data, to make
+        // some of the rendering logic a little easier.
+        $status_uninvited = PhabricatorCalendarEventInvitee::STATUS_UNINVITED;
+        $old = $old + array_fill_keys(array_keys($new), $status_uninvited);
+
         if (count($old) === 1
           && count($new) === 1
           && isset($old[$author_phid])) {
@@ -387,6 +391,9 @@
       case self::TYPE_INVITE:
         $text = null;
 
+        $status_uninvited = PhabricatorCalendarEventInvitee::STATUS_UNINVITED;
+        $old = $old + array_fill_keys(array_keys($new), $status_uninvited);
+
         if (count($old) === 1
           && count($new) === 1
           && isset($old[$author_phid])) {