diff --git a/rb/lib/selenium/webdriver/common/platform.rb b/rb/lib/selenium/webdriver/common/platform.rb
index 0cc995acf9bc1..4596e266c25e3 100644
--- a/rb/lib/selenium/webdriver/common/platform.rb
+++ b/rb/lib/selenium/webdriver/common/platform.rb
@@ -30,7 +30,7 @@ def home
       end
 
       def engine
-        @engine ||= defined?(RUBY_ENGINE) ? RUBY_ENGINE.to_sym : :ruby
+        @engine ||= RUBY_ENGINE.to_sym
       end
 
       def os