diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f612da2..7d27bc1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,9 +24,12 @@ jobs:
         run: bundle exec rubocop --fail-level warning --display-only-fail-level-offenses --format github
 
   test:
-    name: Test - ${{ matrix.gemfile }} - Ruby ${{ matrix.ruby }}
+    name: Test - ${{ matrix.gemfile }} - Ruby ${{ matrix.ruby }} - RSpec ${{ matrix.rspec }}
     runs-on: ubuntu-latest
     timeout-minutes: 10
+    permissions:
+      contents: read
+      checks: write
     strategy:
       fail-fast: false
       matrix:
@@ -38,6 +41,7 @@ jobs:
             activesupport-8.0,
             activesupport-8.1,
           ]
+        rspec: ["3", "4"]
         exclude:
           # Rails 7.2 is >= 3.1
           - ruby: "3.0"
@@ -52,9 +56,23 @@ jobs:
             gemfile: activesupport-8.1
           - ruby: 3.1
             gemfile: activesupport-8.1
+          # RSpec 4 only on Ruby 4.0
+          - ruby: "3.0"
+            rspec: "4"
+          - ruby: 3.1
+            rspec: "4"
+          - ruby: 3.2
+            rspec: "4"
+          - ruby: 3.3
+            rspec: "4"
+          - ruby: 3.4
+            rspec: "4"
+          - ruby: 3.5
+            rspec: "4"
 
     env:
       BUNDLE_GEMFILE: ${{ github.workspace }}/gemfiles/${{ matrix.gemfile }}.gemfile
+      RSPEC_VERSION: ${{ matrix.rspec }}
 
     steps:
       - name: Checkout code
diff --git a/Gemfile b/Gemfile
index f857e45..e4ab7d9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,6 +5,9 @@ git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }
 # Specify your gem's dependencies in marsh_grass.gemspec
 gemspec
 
+gem 'rspec', '>= 4.0.0.alpha', '< 5' if ENV['RSPEC_VERSION'] == '4'
+gem 'rspec', '~> 3.6' if ENV['RSPEC_VERSION'] == '3'
+
 group :development, :test do
   gem 'rubocop'
   gem 'rspec_junit_formatter'
diff --git a/marsh_grass.gemspec b/marsh_grass.gemspec
index 921a95c..b7b6ab6 100644
--- a/marsh_grass.gemspec
+++ b/marsh_grass.gemspec
@@ -34,7 +34,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'pry-byebug', '~> 3'
   spec.add_development_dependency 'rake', '~> 13.0'
   spec.add_dependency 'activesupport', '>= 7.1', '< 9.0'
-  spec.add_dependency 'rspec', '~> 3.6'
+  spec.add_dependency 'rspec', '>= 3.6', '< 5'
   spec.add_dependency 'rspec-rails', '~> 6'
   spec.add_dependency 'timecop', '~> 0.9'
 end