diff --git a/.circleci/config.yml b/.circleci/config.yml
index 7aad2eb7a..a8d33025d 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -11,11 +11,11 @@ jobs:
       - checkout
       - run:
           command: |
-            rvm install 2.6.5
-            rvm use ruby-2.6.5
-            export PATH="/opt/circleci/.rvm/rubies/ruby-2.6.5/bin:$PATH"
-            export GEM_HOME="/opt/circleci/.rvm/gems/ruby-2.6.5"
-            export GEM_PATH="/opt/circleci/.rvm/gems/ruby-2.6.5"
+            rvm install 2.6.6
+            rvm use ruby-2.6.6
+            export PATH="/opt/circleci/.rvm/rubies/ruby-2.6.6/bin:$PATH"
+            export GEM_HOME="/opt/circleci/.rvm/gems/ruby-2.6.6"
+            export GEM_PATH="/opt/circleci/.rvm/gems/ruby-2.6.6"
             gem install bundler -v 2.1.0
             bundle install
             bundle exec rake hatchet:setup_ci
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1e36f7d71..488ed6d66 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## Master (unreleased)
 
+* Default Ruby version is now 2.6.6 (https://github.com/heroku/heroku-buildpack-ruby/pull/974)
+
 ## v213 (4/1/2020)
 
 * Fix regression. PATH value at runtime was relative instead of absolute (https://github.com/heroku/heroku-buildpack-ruby/pull/973)
diff --git a/Gemfile b/Gemfile
index 161c219e6..9836203a0 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,7 +1,7 @@
 source "https://rubygems.org"
 git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
-ruby '2.6.5'
+ruby '2.6.6'
 
 group :development, :test do
   gem "toml-rb"
diff --git a/Gemfile.lock b/Gemfile.lock
index 645470078..6732be4fa 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -97,7 +97,7 @@ DEPENDENCIES
   toml-rb
 
 RUBY VERSION
-   ruby 2.6.5p114
+   ruby 2.6.6p146
 
 BUNDLED WITH
-   2.0.2
+   2.1.4
diff --git a/buildpack.toml b/buildpack.toml
index ee89b3a9c..6526491b9 100644
--- a/buildpack.toml
+++ b/buildpack.toml
@@ -4,7 +4,7 @@ api = "0.2"
 id = "heroku/ruby"
 version = "0.0.1"
 name = "Ruby"
-ruby_version = "2.6.5"
+ruby_version = "2.6.6"
 
   [publish.Ignore]
   files = [
@@ -17,13 +17,13 @@ ruby_version = "2.6.5"
   dir = "."
   files = ["./.env"]
   [[publish.Vendor]]
-  url = "https://s3-external-1.amazonaws.com/heroku-buildpack-ruby/cedar-14/ruby-2.6.5.tgz"
+  url = "https://s3-external-1.amazonaws.com/heroku-buildpack-ruby/cedar-14/ruby-2.6.6.tgz"
   dir = "vendor/ruby/cedar-14"
   [[publish.Vendor]]
-  url = "https://s3-external-1.amazonaws.com/heroku-buildpack-ruby/heroku-16/ruby-2.6.5.tgz"
+  url = "https://s3-external-1.amazonaws.com/heroku-buildpack-ruby/heroku-16/ruby-2.6.6.tgz"
   dir = "vendor/ruby/heroku-16"
   [[publish.Vendor]]
-  url = "https://s3-external-1.amazonaws.com/heroku-buildpack-ruby/heroku-18/ruby-2.6.5.tgz"
+  url = "https://s3-external-1.amazonaws.com/heroku-buildpack-ruby/heroku-18/ruby-2.6.6.tgz"
   dir = "vendor/ruby/heroku-18"
 
 [[stacks]]
diff --git a/changelogs/v213/default_ruby_266.md b/changelogs/v213/default_ruby_266.md
new file mode 100644
index 000000000..e4fda1813
--- /dev/null
+++ b/changelogs/v213/default_ruby_266.md
@@ -0,0 +1,3 @@
+## Default Ruby version for new apps is now 2.6.6
+
+The [default Ruby version for new Ruby applications is 2.6.6](https://devcenter.heroku.com/articles/ruby-support#default-ruby-version-for-new-apps). You’ll only get the default if the application does not specify a ruby version.
diff --git a/lib/language_pack/ruby_version.rb b/lib/language_pack/ruby_version.rb
index 067f78254..6bb113632 100644
--- a/lib/language_pack/ruby_version.rb
+++ b/lib/language_pack/ruby_version.rb
@@ -12,7 +12,7 @@ def initialize(output = "")
       end
     end
 
-    DEFAULT_VERSION_NUMBER = "2.6.5"
+    DEFAULT_VERSION_NUMBER = "2.6.6"
     DEFAULT_VERSION        = "ruby-#{DEFAULT_VERSION_NUMBER}"
     LEGACY_VERSION_NUMBER  = "1.9.2"
     LEGACY_VERSION         = "ruby-#{LEGACY_VERSION_NUMBER}"
diff --git a/lib/language_pack/version.rb b/lib/language_pack/version.rb
index 78bbbc346..69e15f316 100644
--- a/lib/language_pack/version.rb
+++ b/lib/language_pack/version.rb
@@ -2,6 +2,6 @@
 
 module LanguagePack
   class LanguagePack::Base
-    BUILDPACK_VERSION = "v212"
+    BUILDPACK_VERSION = "v213"
   end
 end