diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 343f6ef9f0..735a5ba487 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -26,7 +26,7 @@ jobs:
       fail-fast: false
       matrix:
         os: ['ubuntu-latest', 'macos-latest', 'windows-latest']
-        ruby-version: ['3.4', '3.3', '3.2', '3.1']
+        ruby-version: ['3.4', '3.3', '3.2']
 
     name: Ruby ${{ matrix.ruby-version }} on ${{ matrix.os }}
     steps:
diff --git a/README.md b/README.md
index 29066ff6bd..1fa75b0ea6 100644
--- a/README.md
+++ b/README.md
@@ -30,7 +30,7 @@ Fluentd: Open-Source Log Collector
 
 ### Prerequisites
 
-- Ruby 2.7 or later
+- Ruby 3.2 or later
 - git
 
 `git` should be in `PATH`. On Windows, you can use `Github for Windows` and `GitShell` for easy setup.
diff --git a/fluentd.gemspec b/fluentd.gemspec
index 9888878b57..c7afb175ec 100644
--- a/fluentd.gemspec
+++ b/fluentd.gemspec
@@ -20,7 +20,7 @@ Gem::Specification.new do |gem|
   gem.require_paths = ["lib"]
   gem.license = "Apache-2.0"
 
-  gem.required_ruby_version = '>= 2.7'
+  gem.required_ruby_version = '>= 3.2'
 
   gem.add_runtime_dependency("bundler")
   gem.add_runtime_dependency("msgpack", [">= 1.3.1", "< 2.0.0"])