diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index eb6d4247..89ff0ff5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -38,7 +38,7 @@ jobs:
         # macos is covered in nix ci
         os: ['ubuntu-24.04']
         # Due to https://github.com/actions/runner/issues/849, we have to use quotes for 'n.0'
-        ruby: ['head', '3.3', '3.2']
+        ruby: ['head', '3.4', '3.3']
     runs-on: ${{ matrix.os }}
     env:
       # https://github.com/kachick/ruby-ulid/blob/104834846baf5caa1e8536a11c43acdd56fc849c/CONTRIBUTING.md#adding-dependencies-for-this-gem
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 5caeb68e..57a953b0 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -82,7 +82,7 @@ jobs:
         # - macos-13 # x86_64 - CPU arch does not affect for this gem (I think)
         # - windows-2022 - Too slow. Please tell me if any Windows user is using this gem.
         # For actual use-case, head is needless here
-        ruby: ['3.3', '3.2']
+        ruby: ['3.4', '3.3']
     runs-on: ${{ matrix.os }}
     steps:
       # Required to checkout for gh command
diff --git a/.rubocop.yml b/.rubocop.yml
index f65b8cbc..ea3e3e1b 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -4,7 +4,7 @@ require:
   - rubocop-thread_safety
 
 AllCops:
-  TargetRubyVersion: 3.2
+  TargetRubyVersion: 3.3
   DisplayCopNames: true
   Exclude:
     - '**/vendor/**/*'
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 9ce5dbfb..82088f04 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -136,10 +136,10 @@ $ bundle exec ruby benchmark/the_added_file.rb
 - Basically should be reduced. ref: [#91](kachick/ruby-ulid#91), [#236](kachick/ruby-ulid#236)
 - When having some objects, they should be frozen. ref: [#126](kachick/ruby-ulid#126)
 
-## Tasks to drop Ruby 3.2
+## Tasks to drop Ruby 3.3
 
 - grep `RUBY_VERSION` guards
-- grep `3.2` and `3.3`
+- grep `3.3` and `3.4`
 - Update gemspec and `TargetRubyVersion` in .rubocop.yml
 
 ## Use profiler
diff --git a/README.md b/README.md
index 3aae56d0..e18a704f 100644
--- a/README.md
+++ b/README.md
@@ -38,7 +38,7 @@ Instead, herein is proposed ULID:
 
 ### Install
 
-Tested only in the last 2 Rubies. So you need Ruby 3.2 or higher.
+Tested only in the last 2 Rubies. So you need Ruby 3.3 or higher.
 
 Add this line to your `Gemfile`.
 
diff --git a/ruby-ulid.gemspec b/ruby-ulid.gemspec
index a61ef7da..2073b8cf 100644
--- a/ruby-ulid.gemspec
+++ b/ruby-ulid.gemspec
@@ -23,7 +23,7 @@ Gem::Specification.new do |gem|
     'rubygems_mfa_required' => 'true'
   }
 
-  gem.required_ruby_version = Gem::Requirement.new('>= 3.2')
+  gem.required_ruby_version = Gem::Requirement.new('>= 3.3')
 
   # common