diff --git a/lib/really_simple_captcha/captcha/plain_captcha.rb b/lib/really_simple_captcha/captcha/plain_captcha.rb
index 73ec584..25a7c52 100644
--- a/lib/really_simple_captcha/captcha/plain_captcha.rb
+++ b/lib/really_simple_captcha/captcha/plain_captcha.rb
@@ -1,4 +1,4 @@
-require 'RMagick'
+require 'rmagick'
 require 'base64'
 
 module ReallySimpleCaptcha::Captcha