diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 91fc3a0f..29915c53 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -26,9 +26,6 @@ jobs:
     strategy:
       matrix:
         include:
-          - os: ubuntu-latest
-            ruby: "3.1"
-            task: "--test"
           - os: ubuntu-latest
             ruby: "3.2"
             task: "--test"
@@ -39,13 +36,16 @@ jobs:
             ruby: "3.4"
             task: "--test"
           - os: ubuntu-latest
-            ruby: "3.4"
+            ruby: "4.0"
+            task: "--test"
+          - os: ubuntu-latest
+            ruby: "4.0"
             task: "--rubocop --build --yard --linkinator"
           - os: macos-latest
-            ruby: "3.4"
+            ruby: "4.0"
             task: "--test"
           - os: windows-latest
-            ruby: "3.4"
+            ruby: "4.0"
             task: "--test"
       fail-fast: false
     runs-on: ${{ matrix.os }}
diff --git a/README.md b/README.md
index 4299619b..ba573388 100644
--- a/README.md
+++ b/README.md
@@ -153,7 +153,7 @@ on these and other methods of providing credentials.
 
 ## Supported Ruby Versions
 
-These libraries are currently supported on Ruby 3.0 through Ruby 3.3. Older
+These libraries are currently supported on Ruby 3.2 through Ruby 4.0. Older
 versions of Ruby _may_ still work, but are unsupported and not recommended.
 
 In general, Google provides official support for Ruby versions that are actively
diff --git a/google-cloud-spanner/Gemfile b/google-cloud-spanner/Gemfile
index 5ad8faf3..2580c479 100644
--- a/google-cloud-spanner/Gemfile
+++ b/google-cloud-spanner/Gemfile
@@ -12,6 +12,7 @@ gem "google-cloud-spanner-v1", "~> 1.8"
 gem "google-style", "~> 1.31.0"
 gem "grpc", "~> 1.67"
 gem "grpc-tools", "~> 1.74", ">= 1.74.1"
+gem "irb", "~> 1.17"
 gem "minitest", "~> 5.25"
 gem "minitest-autotest", "~> 1.0"
 gem "minitest-focus", "~> 1.4"
diff --git a/google-cloud-spanner/google-cloud-spanner.gemspec b/google-cloud-spanner/google-cloud-spanner.gemspec
index 2a06589b..cea21209 100644
--- a/google-cloud-spanner/google-cloud-spanner.gemspec
+++ b/google-cloud-spanner/google-cloud-spanner.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |gem|
                       ["OVERVIEW.md", "AUTHENTICATION.md", "LOGGING.md", "CONTRIBUTING.md", "TROUBLESHOOTING.md", "CHANGELOG.md", "CODE_OF_CONDUCT.md", "LICENSE", ".yardopts"]
   gem.require_paths = ["lib"]
 
-  gem.required_ruby_version = ">= 3.1"
+  gem.required_ruby_version = ">= 3.2"
 
   gem.add_dependency "bigdecimal", "~> 3.0"
   gem.add_dependency "concurrent-ruby", "~> 1.0"