diff --git a/Gemfile b/Gemfile
index f3c7dae79..1074a53be 100644
--- a/Gemfile
+++ b/Gemfile
@@ -84,7 +84,7 @@ end
 group :test do
   gem "rails-dom-testing"
   gem 'mocha', '>= 1.4.0'
-  gem 'simplecov', '~> 0.18.5', :require => false
+  gem 'simplecov', '~> 0.21.2', :require => false
   gem "ffi", platforms: [:mingw, :x64_mingw, :mswin]
   # For running system tests
   gem 'puma'