diff --git a/resources/celerity/map.php b/resources/celerity/map.php
--- a/resources/celerity/map.php
+++ b/resources/celerity/map.php
@@ -445,7 +445,7 @@
     'rsrc/js/core/behavior-device.js' => 'a205cf28',
     'rsrc/js/core/behavior-drag-and-drop-textarea.js' => '6d49590e',
     'rsrc/js/core/behavior-error-log.js' => '6882e80a',
-    'rsrc/js/core/behavior-fancy-datepicker.js' => 'ea5cec5d',
+    'rsrc/js/core/behavior-fancy-datepicker.js' => '3ee7ab37',
     'rsrc/js/core/behavior-file-tree.js' => '88236f00',
     'rsrc/js/core/behavior-form.js' => '5c54cbf3',
     'rsrc/js/core/behavior-gesture.js' => '3ab51e2c',
@@ -579,7 +579,7 @@
     'javelin-behavior-durable-column' => 'c72aa091',
     'javelin-behavior-error-log' => '6882e80a',
     'javelin-behavior-event-all-day' => '38dcf3c8',
-    'javelin-behavior-fancy-datepicker' => 'ea5cec5d',
+    'javelin-behavior-fancy-datepicker' => '3ee7ab37',
     'javelin-behavior-global-drag-and-drop' => 'c8e57404',
     'javelin-behavior-herald-rule-editor' => '7ebaeed3',
     'javelin-behavior-high-security-warning' => 'a464fe03',
@@ -1060,6 +1060,13 @@
       'javelin-stratcom',
       'phabricator-tooltip',
     ),
+    '3ee7ab37' => array(
+      'javelin-behavior',
+      'javelin-util',
+      'javelin-dom',
+      'javelin-stratcom',
+      'javelin-vector',
+    ),
     '3f5d6dbf' => array(
       'javelin-behavior',
       'javelin-dom',
@@ -1909,13 +1916,6 @@
       'javelin-dom',
       'phabricator-draggable-list',
     ),
-    'ea5cec5d' => array(
-      'javelin-behavior',
-      'javelin-util',
-      'javelin-dom',
-      'javelin-stratcom',
-      'javelin-vector',
-    ),
     'ea681761' => array(
       'javelin-behavior',
       'javelin-aphlict',
diff --git a/src/view/form/control/AphrontFormDateControl.php b/src/view/form/control/AphrontFormDateControl.php
--- a/src/view/form/control/AphrontFormDateControl.php
+++ b/src/view/form/control/AphrontFormDateControl.php
@@ -259,8 +259,13 @@
       ),
       $time_sel);
 
+    $preferences = $this->user->loadPreferences();
+    $pref_week_start = PhabricatorUserPreferences::PREFERENCE_WEEK_START_DAY;
+    $week_start = $preferences->getPreference($pref_week_start, 0);
+
     Javelin::initBehavior('fancy-datepicker', array(
       'format' => $this->getDateFormat(),
+      'week_start' => $week_start,
       ));
 
     $classes = array();
diff --git a/webroot/rsrc/js/core/behavior-fancy-datepicker.js b/webroot/rsrc/js/core/behavior-fancy-datepicker.js
--- a/webroot/rsrc/js/core/behavior-fancy-datepicker.js
+++ b/webroot/rsrc/js/core/behavior-fancy-datepicker.js
@@ -46,6 +46,16 @@
     return format;
   };
 
+  var get_week_start = function() {
+    var week_start = config.week_start;
+
+    if (week_start === null) {
+      week_start = 0;
+    }
+
+    return week_start;
+  };
+
   var onopen = function(e) {
     e.kill();
 
@@ -277,9 +287,12 @@
     // First, render the weekday names.
     var weekdays = 'SMTWTFS';
     var weekday_names = [];
-    var ii;
-    for (ii = 0; ii < weekdays.length; ii++) {
-      weekday_names.push(cell(weekdays.charAt(ii), null, false, 'day-name'));
+    var week_start = parseInt(get_week_start(), 10);
+    var week_end = parseInt(weekdays.length,10) + week_start;
+
+    for (var ii = week_start; ii < week_end; ii++) {
+      var index = ii%7;
+      weekday_names.push(cell(weekdays.charAt(index), null, false, 'day-name'));
     }
     weeks.push(JX.$N('tr', {}, weekday_names));
 
@@ -290,7 +303,7 @@
     var start = new Date(
       valid_date.getYear() + 1900,
       valid_date.getMonth(),
-      1).getDay();
+      1).getDay() - week_start;
 
     while (start--) {
       days.push(cell('', null, false, 'day-placeholder'));