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
@@ -70,6 +70,12 @@
       $recurrence_end_date_value = clone $end_value;
       $recurrence_end_date_value->setOptional(true);
 
+      $pref_space = PhabricatorUserPreferences::PREFERENCE_CALENDAR_SPACE;
+      $preferences = $viewer->loadPreferences();
+      $space = $preferences->getPreference(
+        $pref_space,
+        $viewer->getDefaultSpacePHID());
+
       $submit_label = pht('Create');
       $page_title = pht('Create Event');
       $redirect = 'created';
@@ -137,6 +143,7 @@
         }
       }
 
+      $space = $event->getSpacePHID();
       $cancel_uri = '/'.$event->getMonogram();
     }
 
@@ -158,7 +165,6 @@
     $icon = $event->getIcon();
     $edit_policy = $event->getEditPolicy();
     $view_policy = $event->getViewPolicy();
-    $space = $event->getSpacePHID();
 
     if ($request->isFormPost()) {
       $xactions = array();
diff --git a/src/applications/settings/panel/PhabricatorDateTimeSettingsPanel.php b/src/applications/settings/panel/PhabricatorDateTimeSettingsPanel.php
--- a/src/applications/settings/panel/PhabricatorDateTimeSettingsPanel.php
+++ b/src/applications/settings/panel/PhabricatorDateTimeSettingsPanel.php
@@ -18,6 +18,8 @@
     $user = $request->getUser();
     $username = $user->getUsername();
 
+    $space_phid = $user->getDefaultSpacePHID();
+    $pref_event_space = PhabricatorUserPreferences::PREFERENCE_CALENDAR_SPACE;
     $pref_time = PhabricatorUserPreferences::PREFERENCE_TIME_FORMAT;
     $pref_date = PhabricatorUserPreferences::PREFERENCE_DATE_FORMAT;
     $pref_week_start = PhabricatorUserPreferences::PREFERENCE_WEEK_START_DAY;
@@ -41,7 +43,10 @@
           $request->getStr($pref_date))
         ->setPreference(
           $pref_week_start,
-          $request->getStr($pref_week_start));
+          $request->getStr($pref_week_start))
+        ->setPreference(
+          $pref_event_space,
+          $request->getStr($pref_event_space));
 
       if (!$errors) {
         $preferences->save();
@@ -93,10 +98,26 @@
           ->setName($pref_week_start)
           ->setCaption(
             pht('Calendar weeks will start with this day.'))
-          ->setValue($preferences->getPreference($pref_week_start, 0)))
-      ->appendChild(
-        id(new AphrontFormSubmitControl())
-          ->setValue(pht('Save Account Settings')));
+          ->setValue($preferences->getPreference($pref_week_start, 0)));
+
+    if (PhabricatorSpacesNamespaceQuery::getViewerSpacesExist($user)) {
+      $form->appendChild(
+      id(new AphrontFormSelectControl())
+        ->setOptions(
+          PhabricatorSpacesNamespaceQuery::getSpaceOptionsForViewer(
+            $user,
+            $space_phid))
+        ->setLabel(pht('Default Calendar Space'))
+        ->setCaption(
+          pht('Calendar events will default to the visibility of '.
+            'this space.'))
+        ->setName($pref_event_space)
+        ->setValue($preferences->getPreference($pref_event_space)));
+    }
+
+    $form->appendChild(
+      id(new AphrontFormSubmitControl())
+        ->setValue(pht('Save Account Settings')));
 
     $form_box = id(new PHUIObjectBoxView())
       ->setHeaderText(pht('Date and Time Settings'))
diff --git a/src/applications/settings/storage/PhabricatorUserPreferences.php b/src/applications/settings/storage/PhabricatorUserPreferences.php
--- a/src/applications/settings/storage/PhabricatorUserPreferences.php
+++ b/src/applications/settings/storage/PhabricatorUserPreferences.php
@@ -11,6 +11,7 @@
   const PREFERENCE_DATE_FORMAT          = 'date-format';
   const PREFERENCE_TIME_FORMAT          = 'time-format';
   const PREFERENCE_WEEK_START_DAY       = 'week-start-day';
+  const PREFERENCE_CALENDAR_SPACE       = 'calendar-space';
 
   const PREFERENCE_RE_PREFIX            = 're-prefix';
   const PREFERENCE_NO_SELF_MAIL         = 'self-mail';