diff --git a/Gemfile b/Gemfile
index ff25b35544..e85d4073dc 100644
--- a/Gemfile
+++ b/Gemfile
@@ -18,6 +18,7 @@ gem "rake", "~>12.0", :group => [:development, :test]
 gem "rake-compiler", "~>1.0.3", :group => [:development, :test]
 gem "rake-compiler-dock", "~>0.7.0", :group => [:development, :test]
 gem "rexical", "~>1.0.5", :group => [:development, :test]
+gem "rubocop", "~>0.73", :group => [:development, :test]
 gem "simplecov", "~>0.16", :group => [:development, :test]
 gem "rdoc", ">=4.0", "<6", :group => [:development, :test]
 
diff --git a/Rakefile b/Rakefile
index 6646df5102..f2af75e346 100644
--- a/Rakefile
+++ b/Rakefile
@@ -144,6 +144,7 @@ HOE = Hoe.spec 'nokogiri' do
     ["rake-compiler",      "~> 1.0.3"],
     ["rake-compiler-dock", "~> 0.7.0"],
     ["rexical",            "~> 1.0.5"],
+    ["rubocop",            "~> 0.73"],
     ["simplecov",          "~> 0.16"],
   ]