diff --git a/src/applications/settings/controller/PhabricatorSettingsTimezoneController.php b/src/applications/settings/controller/PhabricatorSettingsTimezoneController.php
--- a/src/applications/settings/controller/PhabricatorSettingsTimezoneController.php
+++ b/src/applications/settings/controller/PhabricatorSettingsTimezoneController.php
@@ -113,6 +113,11 @@
   }
 
   private function formatOffset($offset) {
+    // This controller works with client-side (Javascript) offsets, which have
+    // the opposite sign we might expect -- for example "UTC-3" is a positive
+    // offset. Invert the sign before rendering the offset.
+    $offset = -1 * $offset;
+
     $hours = $offset / 60;
     // Non-integer number of hours off UTC?
     if ($offset % 60) {
diff --git a/src/applications/settings/setting/PhabricatorTimezoneSetting.php b/src/applications/settings/setting/PhabricatorTimezoneSetting.php
--- a/src/applications/settings/setting/PhabricatorTimezoneSetting.php
+++ b/src/applications/settings/setting/PhabricatorTimezoneSetting.php
@@ -57,11 +57,11 @@
     $groups = array();
     foreach ($timezones as $timezone) {
       $zone = new DateTimeZone($timezone);
-      $offset = -($zone->getOffset($now) / (60 * 60));
+      $offset = ($zone->getOffset($now) / 60);
       $groups[$offset][] = $timezone;
     }
 
-    krsort($groups);
+    ksort($groups);
 
     $option_groups = array(
       array(
@@ -71,10 +71,13 @@
     );
 
     foreach ($groups as $offset => $group) {
-      if ($offset >= 0) {
-        $label = pht('UTC-%d', $offset);
+      $hours = $offset / 60;
+      $minutes = abs($offset % 60);
+
+      if ($offset % 60) {
+        $label = pht('UTC%+d:%02d', $hours, $minutes);
       } else {
-        $label = pht('UTC+%d', -$offset);
+        $label = pht('UTC%+d', $hours);
       }
 
       sort($group);