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
@@ -136,6 +136,14 @@
     return $date;
   }
 
+  private function getTimeFormat() {
+    $viewer = $this->getUser();
+    $preferences = $viewer->loadPreferences();
+    $pref_time_format = PhabricatorUserPreferences::PREFERENCE_TIME_FORMAT;
+
+    return $preferences->getPreference($pref_time_format, 'g:i A');
+  }
+
   private function getDateFormat() {
     $viewer = $this->getUser();
     $preferences = $viewer->loadPreferences();
@@ -233,6 +241,7 @@
       'startTimeID' => $time_id,
       'endTimeID' => $this->endDateID,
       'timeValues' => $values,
+      'format' => $this->getTimeFormat(),
       ));
 
 
@@ -335,20 +344,31 @@
   }
 
   private function getTimeTypeaheadValues() {
+    $time_format = $this->getTimeFormat();
     $times = array();
-    $am_pm_list = array('AM', 'PM');
 
-    foreach ($am_pm_list as $am_pm) {
-      for ($hour = 0; $hour < 12; $hour++) {
-        $actual_hour = ($hour == 0) ? 12 : $hour;
-        $times[] = $actual_hour.':00 '.$am_pm;
-        $times[] = $actual_hour.':30 '.$am_pm;
+    if ($time_format == 'g:i A') {
+      $am_pm_list = array('AM', 'PM');
+
+      foreach ($am_pm_list as $am_pm) {
+        for ($hour = 0; $hour < 12; $hour++) {
+          $actual_hour = ($hour == 0) ? 12 : $hour;
+          $times[] = $actual_hour.':00 '.$am_pm;
+          $times[] = $actual_hour.':30 '.$am_pm;
+        }
+      }
+    } else if ($time_format == 'H:i') {
+      for ($hour = 0; $hour < 24; $hour++) {
+        $written_hour = ($hour > 9) ? $hour : '0'.$hour;
+        $times[] = $written_hour.':00';
+        $times[] = $written_hour.':30';
       }
     }
 
     foreach ($times as $key => $time) {
       $times[$key] = array($key, $time);
     }
+
     return $times;
   }
 
diff --git a/src/view/form/control/AphrontFormDateControlValue.php b/src/view/form/control/AphrontFormDateControlValue.php
--- a/src/view/form/control/AphrontFormDateControlValue.php
+++ b/src/view/form/control/AphrontFormDateControlValue.php
@@ -66,12 +66,13 @@
 
     $value = new AphrontFormDateControlValue();
     $value->viewer = $viewer;
-    $value->valueDate = $value->getFormattedDateFromParts(
-      $year,
-      $month,
-      $day,
-      $value);
-    $value->valueTime = coalesce($time, '12:00 AM');
+    list($value->valueDate, $value->valueTime) =
+      $value->getFormattedDateFromParts(
+        $year,
+        $month,
+        $day,
+        coalesce($time, '12:00 AM'),
+        $value);
     $value->valueEnabled = $enabled;
 
     return $value;
@@ -81,11 +82,12 @@
     $value = new AphrontFormDateControlValue();
     $value->viewer = $request->getViewer();
 
-    $value->valueDate = $value->getFormattedDateFromDate(
-      $request->getStr($key.'_d'),
-      $value);
+    list($value->valueDate, $value->valueTime) =
+      $value->getFormattedDateFromDate(
+        $request->getStr($key.'_d'),
+        $request->getStr($key.'_t'),
+        $value);
 
-    $value->valueTime = $request->getStr($key.'_t');
     $value->valueEnabled = $request->getStr($key.'_e');
     return $value;
   }
@@ -99,14 +101,15 @@
     $year  = $readable[0];
     $month = $readable[1];
     $day   = $readable[2];
+    $time  = $readable[3];
 
-    $value->valueDate = $value->getFormattedDateFromParts(
-      $year,
-      $month,
-      $day,
-      $value);
-    $value->valueTime  = $readable[3];
-
+    list($value->valueDate, $value->valueTime) =
+      $value->getFormattedDateFromParts(
+        $year,
+        $month,
+        $day,
+        $time,
+        $value);
 
     return $value;
   }
@@ -117,11 +120,12 @@
     $value = new AphrontFormDateControlValue();
     $value->viewer = $viewer;
 
-    $value->valueDate = $value->getFormattedDateFromDate(
-      idx($dictionary, 'd'),
-      $value);
+    list($value->valueDate, $value->valueTime) =
+      $value->getFormattedDateFromDate(
+        idx($dictionary, 'd'),
+        idx($dictionary, 't'),
+        $value);
 
-    $value->valueTime = idx($dictionary, 't');
     $value->valueEnabled = idx($dictionary, 'e');
 
     return $value;
@@ -200,6 +204,13 @@
     return $value;
   }
 
+  private function getTimeFormat() {
+    $preferences = $this->viewer->loadPreferences();
+    $pref_time_format = PhabricatorUserPreferences::PREFERENCE_TIME_FORMAT;
+
+    return $preferences->getPreference($pref_time_format, 'g:i A');
+  }
+
   private function getDateFormat() {
     $preferences = $this->viewer->loadPreferences();
     $pref_date_format = PhabricatorUserPreferences::PREFERENCE_DATE_FORMAT;
@@ -207,7 +218,7 @@
     return $preferences->getPreference($pref_date_format, 'Y-m-d');
   }
 
-  private function getFormattedDateFromDate($date, $value) {
+  private function getFormattedDateFromDate($date, $time, $value) {
     $original_input = $date;
     $zone = $value->getTimezone();
     $separator = $value->getFormatSeparator();
@@ -216,17 +227,32 @@
     $date = id(new DateTime($date, $zone));
 
     if ($date) {
-      return $date->format($value->getDateFormat());
+      $date = $date->format($value->getDateFormat());
     } else {
-      return $original_input;
+      $date = $original_input;
     }
+
+    $date = id(new DateTime("{$date} {$time}", $zone));
+
+    return array(
+      $date->format($value->getDateFormat()),
+      $date->format($value->getTimeFormat()),
+    );
   }
 
-  private function getFormattedDateFromParts($year, $month, $day, $value) {
+  private function getFormattedDateFromParts(
+    $year,
+    $month,
+    $day,
+    $time,
+    $value) {
     $zone = $value->getTimezone();
+    $date_time = id(new DateTime("{$year}-{$month}-{$day} {$time}", $zone));
 
-    return id(new DateTime("{$year}-{$month}-{$day}", $zone))
-      ->format($value->getDateFormat());
+    return array(
+      $date_time->format($value->getDateFormat()),
+      $date_time->format($value->getTimeFormat()),
+    );
   }
 
   private function getFormatSeparator() {
diff --git a/webroot/rsrc/js/core/behavior-time-typeahead.js b/webroot/rsrc/js/core/behavior-time-typeahead.js
--- a/webroot/rsrc/js/core/behavior-time-typeahead.js
+++ b/webroot/rsrc/js/core/behavior-time-typeahead.js
@@ -11,6 +11,7 @@
 JX.behavior('time-typeahead', function(config) {
   var start_date_control = JX.$(config.startTimeID);
   var end_date_control = config.endTimeID ? JX.$(config.endTimeID) : null;
+  var format = config.format;
 
   var end_date_tampered = false;
 
@@ -79,7 +80,7 @@
 
 
   function getNewValue(time) {
-    var regex = /^([01]?\d)(?::([0-5]\d))?\s*((am|pm))?$/i;
+    var regex = /^([0-2]?\d)(?::([0-5]\d))?\s*((am|pm))?$/i;
 
     if (!regex.test(time)) {
       return null;
@@ -90,32 +91,56 @@
     var minutes = parseInt(results[2], 10) ? parseInt(results[2], 10) : 0;
 
     var real_time = 0;
-
-    if (/pm/i.test(results[3])) {
-      real_time = 12*60;
-    } else if (/am/i.test(results[3]) && hours == 12) {
-      hours = 0;
+    var end_value = '';
+
+    var end_hours;
+    var end_minutes;
+
+    if (format === 'H:i' && hours < 23) {
+      end_hours = hours + 1;
+
+      if (end_hours > 9) {
+        end_hours = end_hours.toString();
+      } else {
+        end_hours = '0' + end_hours.toString();
+      }
+
+      if (minutes > 9) {
+        end_minutes = minutes.toString();
+      } else {
+        end_minutes = '0' + minutes.toString();
+      }
+
+      end_value = end_hours + ':' + end_minutes;
+    } else if (format === 'g:i A') {
+      if (/pm/i.test(results[3])) {
+        real_time = 12*60;
+      } else if (/am/i.test(results[3]) && hours == 12) {
+        hours = 0;
+      }
+
+      real_time = real_time + (hours * 60) + minutes;
+
+      var end_time = real_time + 60;
+
+      var end_meridian = 'AM';
+      end_hours = Math.floor(end_time / 60);
+
+      if (end_hours == 12) {
+        end_meridian = 'PM';
+      } else if (end_hours > 12 && end_hours < 24) {
+        end_hours = end_hours - 12;
+        end_meridian = 'PM';
+      } else if (end_hours == 24) {
+        end_hours = end_hours - 12;
+      }
+
+      end_minutes = end_time%60;
+      end_minutes = (end_minutes < 9) ? end_minutes : ('0' + end_minutes);
+      end_value = end_hours + ':' + end_minutes + ' ' + end_meridian;
     }
 
-    real_time = real_time + (hours * 60) + minutes;
-
-    var end_time = real_time + 60;
-
-    var end_meridian = 'AM';
-    var end_hours = Math.floor(end_time / 60);
-
-    if (end_hours == 12) {
-      end_meridian = 'PM';
-    } else if (end_hours > 12 && end_hours < 24) {
-      end_hours = end_hours - 12;
-      end_meridian = 'PM';
-    } else if (end_hours == 24) {
-      end_hours = end_hours - 12;
-    }
 
-    var end_minutes = end_time%60;
-    end_minutes = (end_minutes > 9) ? end_minutes : ('0' + end_minutes);
-    var end_value = end_hours + ':' + end_minutes + ' ' + end_meridian;
     return end_value;
   }