diff --git a/ruby-jwt.gemspec b/ruby-jwt.gemspec
index 362e467c..02e06e58 100644
--- a/ruby-jwt.gemspec
+++ b/ruby-jwt.gemspec
@@ -24,7 +24,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'bundler'
   spec.add_development_dependency 'rake'
   spec.add_development_dependency 'rspec'
-  spec.add_development_dependency 'simplecov'
+  spec.add_development_dependency 'simplecov', '< 0.18'
   spec.add_development_dependency 'simplecov-json'
   spec.add_development_dependency 'codeclimate-test-reporter'
   spec.add_development_dependency 'codacy-coverage'