diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index 73232e3..29edbf0 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -12,7 +12,7 @@ jobs:
     - uses: actions/checkout@v3
     - uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 3.4
+        ruby-version: '4.0'
         bundler-cache: true
     - run: |
         bundle exec rake test spinach
diff --git a/.github/workflows/danger.yml b/.github/workflows/danger.yml
index bd89a88..bf1c19f 100644
--- a/.github/workflows/danger.yml
+++ b/.github/workflows/danger.yml
@@ -9,5 +9,5 @@ jobs:
     uses: numbata/danger-pr-comment/.github/workflows/danger-run.yml@v0.1.0
     secrets: inherit
     with:
-      ruby-version: '3.4'
+      ruby-version: '4.0'
       bundler-cache: true
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 7c6d5b3..76ba84a 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -10,7 +10,7 @@ jobs:
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: '2.7'
+          ruby-version: '4.0'
           bundler-cache: true
       - run: bundle exec rubocop
 
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index ff75f78..624c5d2 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -8,6 +8,7 @@ jobs:
       fail-fast: false
       matrix:
         entry:
+          - { ruby: '4.0' }
           - { ruby: '3.4' }
           - { ruby: '3.2' }
           - { ruby: '2.7' }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 97f38a0..07904be 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 * [#298](https://github.com/codegram/hyperclient/pull/300): Upgraded RuboCop to 1.80.2 - [@dblock](https://github.com/dblock).
 * [#298](https://github.com/codegram/hyperclient/pull/298): Upgraded RuboCop to 1.63.5 - [@dblock](https://github.com/dblock).
+* [#321](https://github.com/codegram/hyperclient/pull/321): Added Ruby 4.0 to the CI test matrix - [@dblock](https://github.com/dblock).
 * Your contribution here.
 
 ### 2.0.0 (2024/02/01)