diff --git a/lib/singed/rspec.rb b/lib/singed/rspec.rb
index 9445b9c..fb16285 100644
--- a/lib/singed/rspec.rb
+++ b/lib/singed/rspec.rb
@@ -1,5 +1,7 @@
 require 'singed'
 
+return unless defined?(RSpec)
+
 RSpec.configure do |config|
   config.around do |example|
     if example.metadata[:flamegraph]