diff --git a/README.md b/README.md
index a7e6d80..5119aef 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,7 @@
 </dl>
 
 [![Build Status](https://secure.travis-ci.org/google/google-auth-library-ruby.png)](http://travis-ci.org/google/google-auth-library-ruby)
+[![Coverage Status](https://coveralls.io/repos/google/google-auth-library-ruby/badge.png)](https://coveralls.io/r/google/google-auth-library-ruby)
 [![Dependency Status](https://gemnasium.com/google/google-auth-library-ruby.png)](https://gemnasium.com/google/google-auth-library-ruby)
 
 ## Description
diff --git a/googleauth.gemspec b/googleauth.gemspec
index 43ae121..ed3ea0e 100755
--- a/googleauth.gemspec
+++ b/googleauth.gemspec
@@ -33,6 +33,7 @@ Gem::Specification.new do |s|
   s.add_dependency 'signet', '~> 0.6.0'
 
   s.add_development_dependency 'bundler', '~> 1.7'
+  s.add_development_dependency 'simplecov', '~> 0.9.2'
   s.add_development_dependency 'rake', '~> 10.0'
   s.add_development_dependency 'rubocop', '~> 0.28.0'
   s.add_development_dependency 'rspec', '~> 3.0'
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 837d2fc..8dc1604 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -39,6 +39,8 @@ require 'faraday'
 require 'rspec'
 require 'logging'
 require 'rspec/logging_helper'
+require 'simplecov'
+SimpleCov.start
 
 # Allow Faraday to support test stubs
 Faraday::Adapter.load_middleware(:test)