diff --git a/.rubocop.yml b/.rubocop.yml
index c836f650..2830acd4 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -8,7 +8,7 @@ require:
   - rubocop-minitest
 
 AllCops:
-  TargetRubyVersion: 2.3
+  TargetRubyVersion: 2.4
 
 Naming/PredicateName:
   # Method define macros for dynamically generated method.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d34bde1a..c7af3ee0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 ### Changes
 
 * [#73](https://github.com/rubocop-hq/rubocop-minitest/issues/73): The Minitest department works on file names end with `_test.rb` by default. ([@koic][])
+* [#77](https://github.com/rubocop-hq/rubocop-minitest/pull/77): **(BREAKING)** Drop support for Ruby 2.3. ([@koic][])
 
 ## 0.8.1 (2020-04-06)
 
diff --git a/rubocop-minitest.gemspec b/rubocop-minitest.gemspec
index 7594d1e5..a054dc2d 100644
--- a/rubocop-minitest.gemspec
+++ b/rubocop-minitest.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |spec|
   DESCRIPTION
   spec.license = 'MIT'
 
-  spec.required_ruby_version = '>= 2.3.0'
+  spec.required_ruby_version = '>= 2.4.0'
   spec.metadata = {
     'homepage_uri' => 'https://docs.rubocop.org/projects/minitest/',
     'changelog_uri' => 'https://github.com/rubocop-hq/rubocop-minitest/blob/master/CHANGELOG.md',
diff --git a/test/assertion_helper.rb b/test/assertion_helper.rb
index 3d4a8f9a..9bac5610 100644
--- a/test/assertion_helper.rb
+++ b/test/assertion_helper.rb
@@ -87,6 +87,6 @@ def parse_source!(source, file = nil)
   end
 
   def ruby_version
-    2.3
+    2.4
   end
 end