diff --git a/src/applications/config/check/PhabricatorSetupCheckExtensions.php b/src/applications/config/check/PhabricatorSetupCheckExtensions.php
index 87f1bcd6dd..89ad012adf 100644
--- a/src/applications/config/check/PhabricatorSetupCheckExtensions.php
+++ b/src/applications/config/check/PhabricatorSetupCheckExtensions.php
@@ -1,52 +1,53 @@
 <?php
 
 final class PhabricatorSetupCheckExtensions extends PhabricatorSetupCheck {
 
   public function getExecutionOrder() {
     return 0;
   }
 
   protected function executeChecks() {
     // TODO: Make 'mbstring' and 'iconv' soft requirements.
     // TODO: Make 'curl' a soft requirement.
 
     $required = array(
       'hash',
       'json',
       'openssl',
       'mbstring',
       'iconv',
+      'ctype',
 
       // There is a chance we might not need this, but some configurations (like
       // OAuth or Amazon SES) will require it. Just mark it 'required' since
       // it's widely available and relatively core.
       'curl',
     );
 
     $need = array();
     foreach ($required as $extension) {
       if (!extension_loaded($extension)) {
         $need[] = $extension;
       }
     }
 
     if (!extension_loaded('mysqli') && !extension_loaded('mysql')) {
       $need[] = 'mysqli or mysql';
     }
 
     if (!$need) {
       return;
     }
 
     $message = pht('Required PHP extensions are not installed.');
 
     $issue = $this->newIssue('php.extensions')
       ->setIsFatal(true)
       ->setName(pht('Missing Required Extensions'))
       ->setMessage($message);
 
     foreach ($need as $extension) {
       $issue->addPHPExtension($extension);
     }
   }
 }