diff --git a/Services/Twilio/Rest/Sip.php b/Services/Twilio/Rest/Sip.php
index <HASH>..<HASH> 100644
--- a/Services/Twilio/Rest/Sip.php
+++ b/Services/Twilio/Rest/Sip.php
@@ -4,7 +4,7 @@
  * For Linux filename compatibility, this file needs to be named Sip.php, or
  * camelize() needs to be special cased in setupSubresources
  */
-class Services_Twilio_Rest_SIP extends Services_Twilio_InstanceResource {
+class Services_Twilio_Rest_Sip extends Services_Twilio_InstanceResource {
     protected function init($client, $uri) {
         $this->setupSubresources(
             'domains',
Change class name to match filename

This is required in Linux for PSR-0.