diff --git a/lib/guard/rspec/runner.rb b/lib/guard/rspec/runner.rb
index 760790f3..f76670e2 100644
--- a/lib/guard/rspec/runner.rb
+++ b/lib/guard/rspec/runner.rb
@@ -50,8 +50,8 @@ def _run(paths, failed_paths, options)
       end
 
       def _without_bundler_env
-        if defined?(Bundler)
-          Bundler.with_clean_env { yield }
+        if defined?(::Bundler)
+          ::Bundler.with_clean_env { yield }
         else
           yield
         end