diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -2026,6 +2026,8 @@
     'PhabricatorCalendarEventCancelTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventCancelTransaction.php',
     'PhabricatorCalendarEventDateTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventDateTransaction.php',
     'PhabricatorCalendarEventDeclineTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventDeclineTransaction.php',
+    'PhabricatorCalendarEventDefaultEditCapability' => 'applications/calendar/capability/PhabricatorCalendarEventDefaultEditCapability.php',
+    'PhabricatorCalendarEventDefaultViewCapability' => 'applications/calendar/capability/PhabricatorCalendarEventDefaultViewCapability.php',
     'PhabricatorCalendarEventDescriptionTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventDescriptionTransaction.php',
     'PhabricatorCalendarEventDragController' => 'applications/calendar/controller/PhabricatorCalendarEventDragController.php',
     'PhabricatorCalendarEventEditConduitAPIMethod' => 'applications/calendar/conduit/PhabricatorCalendarEventEditConduitAPIMethod.php',
@@ -2036,11 +2038,13 @@
     'PhabricatorCalendarEventEndDateTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventEndDateTransaction.php',
     'PhabricatorCalendarEventFrequencyTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventFrequencyTransaction.php',
     'PhabricatorCalendarEventFulltextEngine' => 'applications/calendar/search/PhabricatorCalendarEventFulltextEngine.php',
+    'PhabricatorCalendarEventHostPolicyRule' => 'applications/calendar/policyrule/PhabricatorCalendarEventHostPolicyRule.php',
     'PhabricatorCalendarEventHostTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventHostTransaction.php',
     'PhabricatorCalendarEventIconTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventIconTransaction.php',
     'PhabricatorCalendarEventInviteTransaction' => 'applications/calendar/xaction/PhabricatorCalendarEventInviteTransaction.php',
     'PhabricatorCalendarEventInvitee' => 'applications/calendar/storage/PhabricatorCalendarEventInvitee.php',
     'PhabricatorCalendarEventInviteeQuery' => 'applications/calendar/query/PhabricatorCalendarEventInviteeQuery.php',
+    'PhabricatorCalendarEventInviteesPolicyRule' => 'applications/calendar/policyrule/PhabricatorCalendarEventInviteesPolicyRule.php',
     'PhabricatorCalendarEventJoinController' => 'applications/calendar/controller/PhabricatorCalendarEventJoinController.php',
     'PhabricatorCalendarEventListController' => 'applications/calendar/controller/PhabricatorCalendarEventListController.php',
     'PhabricatorCalendarEventMailReceiver' => 'applications/calendar/mail/PhabricatorCalendarEventMailReceiver.php',
@@ -6654,6 +6658,8 @@
     'PhabricatorCalendarEventCancelTransaction' => 'PhabricatorCalendarEventTransactionType',
     'PhabricatorCalendarEventDateTransaction' => 'PhabricatorCalendarEventTransactionType',
     'PhabricatorCalendarEventDeclineTransaction' => 'PhabricatorCalendarEventReplyTransaction',
+    'PhabricatorCalendarEventDefaultEditCapability' => 'PhabricatorPolicyCapability',
+    'PhabricatorCalendarEventDefaultViewCapability' => 'PhabricatorPolicyCapability',
     'PhabricatorCalendarEventDescriptionTransaction' => 'PhabricatorCalendarEventTransactionType',
     'PhabricatorCalendarEventDragController' => 'PhabricatorCalendarController',
     'PhabricatorCalendarEventEditConduitAPIMethod' => 'PhabricatorEditEngineAPIMethod',
@@ -6664,6 +6670,7 @@
     'PhabricatorCalendarEventEndDateTransaction' => 'PhabricatorCalendarEventDateTransaction',
     'PhabricatorCalendarEventFrequencyTransaction' => 'PhabricatorCalendarEventTransactionType',
     'PhabricatorCalendarEventFulltextEngine' => 'PhabricatorFulltextEngine',
+    'PhabricatorCalendarEventHostPolicyRule' => 'PhabricatorPolicyRule',
     'PhabricatorCalendarEventHostTransaction' => 'PhabricatorCalendarEventTransactionType',
     'PhabricatorCalendarEventIconTransaction' => 'PhabricatorCalendarEventTransactionType',
     'PhabricatorCalendarEventInviteTransaction' => 'PhabricatorCalendarEventTransactionType',
@@ -6672,6 +6679,7 @@
       'PhabricatorPolicyInterface',
     ),
     'PhabricatorCalendarEventInviteeQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
+    'PhabricatorCalendarEventInviteesPolicyRule' => 'PhabricatorPolicyRule',
     'PhabricatorCalendarEventJoinController' => 'PhabricatorCalendarController',
     'PhabricatorCalendarEventListController' => 'PhabricatorCalendarController',
     'PhabricatorCalendarEventMailReceiver' => 'PhabricatorObjectMailReceiver',
diff --git a/src/applications/calendar/application/PhabricatorCalendarApplication.php b/src/applications/calendar/application/PhabricatorCalendarApplication.php
--- a/src/applications/calendar/application/PhabricatorCalendarApplication.php
+++ b/src/applications/calendar/application/PhabricatorCalendarApplication.php
@@ -83,4 +83,19 @@
     );
   }
 
+  protected function getCustomCapabilities() {
+    return array(
+      PhabricatorCalendarEventDefaultViewCapability::CAPABILITY => array(
+        'caption' => pht('Default view policy for newly created events.'),
+        'template' => PhabricatorCalendarEventPHIDType::TYPECONST,
+        'capability' => PhabricatorPolicyCapability::CAN_VIEW,
+      ),
+      PhabricatorCalendarEventDefaultEditCapability::CAPABILITY => array(
+        'caption' => pht('Default edit policy for newly created events.'),
+        'template' => PhabricatorCalendarEventPHIDType::TYPECONST,
+        'capability' => PhabricatorPolicyCapability::CAN_EDIT,
+      ),
+    );
+  }
+
 }
diff --git a/src/applications/calendar/capability/PhabricatorCalendarEventDefaultEditCapability.php b/src/applications/calendar/capability/PhabricatorCalendarEventDefaultEditCapability.php
new file mode 100644
--- /dev/null
+++ b/src/applications/calendar/capability/PhabricatorCalendarEventDefaultEditCapability.php
@@ -0,0 +1,12 @@
+<?php
+
+final class PhabricatorCalendarEventDefaultEditCapability
+  extends PhabricatorPolicyCapability {
+
+  const CAPABILITY = 'calendar.event.default.edit';
+
+  public function getCapabilityName() {
+    return pht('Default Edit Policy');
+  }
+
+}
diff --git a/src/applications/calendar/capability/PhabricatorCalendarEventDefaultViewCapability.php b/src/applications/calendar/capability/PhabricatorCalendarEventDefaultViewCapability.php
new file mode 100644
--- /dev/null
+++ b/src/applications/calendar/capability/PhabricatorCalendarEventDefaultViewCapability.php
@@ -0,0 +1,16 @@
+<?php
+
+final class PhabricatorCalendarEventDefaultViewCapability
+  extends PhabricatorPolicyCapability {
+
+  const CAPABILITY = 'calendar.event.default.view';
+
+  public function getCapabilityName() {
+    return pht('Default View Policy');
+  }
+
+  public function shouldAllowPublicPolicySetting() {
+    return true;
+  }
+
+}
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
@@ -65,6 +65,29 @@
     return $types;
   }
 
+  protected function adjustObjectForPolicyChecks(
+    PhabricatorLiskDAO $object,
+    array $xactions) {
+
+    $copy = parent::adjustObjectForPolicyChecks($object, $xactions);
+    foreach ($xactions as $xaction) {
+      switch ($xaction->getTransactionType()) {
+        case PhabricatorCalendarEventHostTransaction::TRANSACTIONTYPE:
+          $copy->setHostPHID($xaction->getNewValue());
+          break;
+        case PhabricatorCalendarEventInviteTransaction::TRANSACTIONTYPE:
+          PhabricatorPolicyRule::passTransactionHintToRule(
+            $copy,
+            new PhabricatorCalendarEventInviteesPolicyRule(),
+            array_fuse($xaction->getNewValue()));
+          break;
+      }
+    }
+
+    return $copy;
+  }
+
+
   protected function applyFinalEffects(
     PhabricatorLiskDAO $object,
     array $xactions) {
diff --git a/src/applications/calendar/policyrule/PhabricatorCalendarEventHostPolicyRule.php b/src/applications/calendar/policyrule/PhabricatorCalendarEventHostPolicyRule.php
new file mode 100644
--- /dev/null
+++ b/src/applications/calendar/policyrule/PhabricatorCalendarEventHostPolicyRule.php
@@ -0,0 +1,43 @@
+<?php
+
+final class PhabricatorCalendarEventHostPolicyRule
+  extends PhabricatorPolicyRule {
+
+  public function getObjectPolicyKey() {
+    return 'calendar.event.host';
+  }
+
+  public function getObjectPolicyName() {
+    return pht('Event Host');
+  }
+
+  public function getPolicyExplanation() {
+    return pht('The host of this event can take this action.');
+  }
+
+  public function getRuleDescription() {
+    return pht('event host');
+  }
+
+  public function canApplyToObject(PhabricatorPolicyInterface $object) {
+    return ($object instanceof PhabricatorCalendarEvent);
+  }
+
+  public function applyRule(
+    PhabricatorUser $viewer,
+    $value,
+    PhabricatorPolicyInterface $object) {
+
+    $viewer_phid = $viewer->getPHID();
+    if (!$viewer_phid) {
+      return false;
+    }
+
+    return ($object->getHostPHID() == $viewer_phid);
+  }
+
+  public function getValueControlType() {
+    return self::CONTROL_TYPE_NONE;
+  }
+
+}
diff --git a/src/applications/calendar/policyrule/PhabricatorCalendarEventInviteesPolicyRule.php b/src/applications/calendar/policyrule/PhabricatorCalendarEventInviteesPolicyRule.php
new file mode 100644
--- /dev/null
+++ b/src/applications/calendar/policyrule/PhabricatorCalendarEventInviteesPolicyRule.php
@@ -0,0 +1,104 @@
+<?php
+
+final class PhabricatorCalendarEventInviteesPolicyRule
+  extends PhabricatorPolicyRule {
+
+  private $invited = array();
+  private $sourcePHIDs = array();
+
+  public function getObjectPolicyKey() {
+    return 'calendar.event.invitees';
+  }
+
+  public function getObjectPolicyName() {
+    return pht('Event Invitees');
+  }
+
+  public function getPolicyExplanation() {
+    return pht('Users invited to this event can take this action.');
+  }
+
+  public function getRuleDescription() {
+    return pht('event invitees');
+  }
+
+  public function canApplyToObject(PhabricatorPolicyInterface $object) {
+    return ($object instanceof PhabricatorCalendarEvent);
+  }
+
+  public function willApplyRules(
+    PhabricatorUser $viewer,
+    array $values,
+    array $objects) {
+
+    $viewer_phid = $viewer->getPHID();
+    if (!$viewer_phid) {
+      return;
+    }
+
+    if (empty($this->invited[$viewer_phid])) {
+      $this->invited[$viewer_phid] = array();
+    }
+
+    if (!isset($this->sourcePHIDs[$viewer_phid])) {
+      $source_phids = PhabricatorEdgeQuery::loadDestinationPHIDs(
+        $viewer_phid,
+        PhabricatorProjectMemberOfProjectEdgeType::EDGECONST);
+      $source_phids[] = $viewer_phid;
+      $this->sourcePHIDs[$viewer_phid] = $source_phids;
+    }
+
+    foreach ($objects as $key => $object) {
+      $cache = $this->getTransactionHint($object);
+      if ($cache === null) {
+        // We don't have a hint for this object, so we'll deal with it below.
+        continue;
+      }
+
+      // We have a hint, so use that as the source of truth.
+      unset($objects[$key]);
+
+      foreach ($this->sourcePHIDs[$viewer_phid] as $source_phid) {
+        if (isset($cache[$source_phid])) {
+          $this->invited[$viewer_phid][$object->getPHID()] = true;
+          break;
+        }
+      }
+    }
+
+    $phids = mpull($objects, 'getPHID');
+    if (!$phids) {
+      return;
+    }
+
+    $invited = id(new PhabricatorCalendarEventInvitee())->loadAllWhere(
+      'eventPHID IN (%Ls)
+        AND inviteePHID IN (%Ls)
+        AND status != %s',
+      $phids,
+      $this->sourcePHIDs[$viewer_phid],
+      PhabricatorCalendarEventInvitee::STATUS_UNINVITED);
+    $invited = mpull($invited, 'getEventPHID');
+
+    $this->invited[$viewer_phid] += array_fill_keys($invited, true);
+  }
+
+  public function applyRule(
+    PhabricatorUser $viewer,
+    $value,
+    PhabricatorPolicyInterface $object) {
+
+    $viewer_phid = $viewer->getPHID();
+    if (!$viewer_phid) {
+      return false;
+    }
+
+    $invited = idx($this->invited, $viewer_phid);
+    return isset($invited[$object->getPHID()]);
+  }
+
+  public function getValueControlType() {
+    return self::CONTROL_TYPE_NONE;
+  }
+
+}
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
@@ -57,7 +57,10 @@
       ->withClasses(array('PhabricatorCalendarApplication'))
       ->executeOne();
 
-    $view_policy = PhabricatorPolicies::getMostOpenPolicy();
+    $view_default = PhabricatorCalendarEventDefaultViewCapability::CAPABILITY;
+    $edit_default = PhabricatorCalendarEventDefaultEditCapability::CAPABILITY;
+    $view_policy = $app->getPolicy($view_default);
+    $edit_policy = $app->getPolicy($edit_default);
 
     $start = new DateTime('@'.PhabricatorTime::getNow());
     $start->setTimeZone($actor->getTimeZone());
@@ -83,7 +86,7 @@
         ))
       ->setIcon($default_icon)
       ->setViewPolicy($view_policy)
-      ->setEditPolicy($actor->getPHID())
+      ->setEditPolicy($edit_policy)
       ->setSpacePHID($actor->getDefaultSpacePHID())
       ->attachInvitees(array())
       ->setDateFrom($epoch_min)