diff --git a/src/repository/api/ArcanistSubversionAPI.php b/src/repository/api/ArcanistSubversionAPI.php
--- a/src/repository/api/ArcanistSubversionAPI.php
+++ b/src/repository/api/ArcanistSubversionAPI.php
@@ -40,6 +40,7 @@
     $argv[0] = 'svn '.$argv[0];
 
     $future = newv('ExecFuture', $argv);
+    $future->setEnv(array('LANG' => 'en_US.UTF-8'));
     $future->setCWD($this->getPath());
     return $future;
   }