diff --git a/.rubocop.yml b/.rubocop.yml
new file mode 100644
index 00000000000..8a002f79f32
--- /dev/null
+++ b/.rubocop.yml
@@ -0,0 +1,13 @@
+inherit_gem:
+  stripe-rubocop: .rubocop.yml
+
+AllCops:
+  Exclude:
+    # Someday we should enable some formatting cops for these
+    - test/testdata/**/*
+    - test/cli/**/*
+
+    # Things we didn't write
+    - bazel-*/**/*
+    - third_party/**/*
+    - parser/tools/generate_diagnostics.rb
diff --git a/.ruby-version b/.ruby-version
new file mode 100644
index 00000000000..6b4950e3de2
--- /dev/null
+++ b/.ruby-version
@@ -0,0 +1 @@
+2.4
diff --git a/Dockerfile b/Dockerfile
index b007efbfe26..8b2b25415b6 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -16,6 +16,8 @@ RUN apt-get update && apt-get install -y ragel bison ruby autoconf
 # Dependencies for pay-server gems
 RUN apt-get update && apt-get install -y libpq-dev libicu-dev libsqlite3-dev
 
+RUN rbenv exec gem install bundler --no-rdoc --no-ri
+
 RUN /usr/stripe/bin/docker/stripe-install-go 1.9 d70eadefce8e160638a9a6db97f7192d8463069ab33138893ad3bf31b0650a79
 ENV GOPATH /gopath
 ENV PATH $PATH:/usr/local/go/bin:$GOPATH/bin
diff --git a/Gemfile b/Gemfile
new file mode 100644
index 00000000000..72303307d07
--- /dev/null
+++ b/Gemfile
@@ -0,0 +1,17 @@
+# rubocop:disable PrisonGuard/NoRequireSideEffects
+
+found = ['~/.', '/etc/'].any? do |file|
+  begin
+    path = File.expand_path(file + 'bundle-gemfile-hook')
+    File.lstat(path)
+  rescue
+    next
+  end
+  instance_eval(File.read(path), path)
+  break true
+end
+source('https://rubygems.org/') if !found
+
+gem 'stripe-rubocop', '0.7.4'
+
+# rubocop:enable PrisonGuard/NoRequireSideEffects
diff --git a/Gemfile.lock b/Gemfile.lock
new file mode 100644
index 00000000000..2950a38e6d8
--- /dev/null
+++ b/Gemfile.lock
@@ -0,0 +1,29 @@
+GEM
+  remote: https://intgems.local.corp.stripe.com:446/
+  specs:
+    ast (2.4.0)
+    parallel (1.12.1)
+    parser (2.4.0.2)
+      ast (~> 2.3)
+    powerpack (0.1.1)
+    rainbow (3.0.0)
+    rubocop (0.52.1)
+      parallel (~> 1.10)
+      parser (>= 2.4.0.2, < 3.0)
+      powerpack (~> 0.1)
+      rainbow (>= 2.2.2, < 4.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (~> 1.0, >= 1.0.1)
+    ruby-progressbar (1.9.0)
+    stripe-rubocop (0.7.4)
+      rubocop (= 0.52.1)
+    unicode-display_width (1.3.0)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  stripe-rubocop (= 0.7.4)
+
+BUNDLED WITH
+   1.16.1
diff --git a/ci/stripe-internal-ruby-typer.sh b/ci/stripe-internal-ruby-typer.sh
index 956c4bc5f8b..0f879826da1 100755
--- a/ci/stripe-internal-ruby-typer.sh
+++ b/ci/stripe-internal-ruby-typer.sh
@@ -6,6 +6,8 @@ set -eux
 ./tools/scripts/lint_sh.sh -t
 ./tools/scripts/generate_compdb_targets.sh -t
 ./tools/scripts/build_compilation_db.sh
+rbenv exec bundle install
+rbenv exec bundle exec rubocop
 
 err=0
 
diff --git a/test/import_whitequark.rb b/test/import_whitequark.rb
index f88778e6450..3fd4376e9f6 100644
--- a/test/import_whitequark.rb
+++ b/test/import_whitequark.rb
@@ -24,4 +24,7 @@ def main
     cur_file = nil
   end
 end
-main
+
+if $0 == __FILE__
+  main
+end
diff --git a/test/t.rb b/test/t.rb
index 59b1e8c0126..b3d10260ac4 100644
--- a/test/t.rb
+++ b/test/t.rb
@@ -1,21 +1,21 @@
+# rubocop:disable PrisonGuard/NoTopLevelDeclarations
 class T
-  def self.type(fixed: nil)
-  end
-  def self.assert_type!(*args)
-  end
-  def self.untyped
-  end
+  def self.type(fixed: nil); end
+  def self.assert_type!(*args); end
+  def self.untyped; end
 end
+
 class T::Sig
-  def returns(*args)
-  end
+  def returns(*args); end
 end
-def sig(*args)
+
+def sig(*_args)
   T::Sig.new
 end
 
 class Module
-  def [](*args)
+  def [](*_args)
     self
   end
 end
+# rubocop:enable PrisonGuard/NoTopLevelDeclarations