diff --git a/lib/twilio-ruby.rb b/lib/twilio-ruby.rb
index 467f05dd7..335b4b48d 100644
--- a/lib/twilio-ruby.rb
+++ b/lib/twilio-ruby.rb
@@ -10,7 +10,7 @@
 require 'json'
 
 require 'twilio-ruby/version' unless defined?(Twilio::VERSION)
-require 'rack/twilio_webhook_authentication'
+require 'rack/twilio_webhook_authentication' if defined?(Rack)
 
 require 'twilio-ruby/util'
 require 'twilio-ruby/security/request_validator'