diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index bb04a94..e1ff5f3 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['3.4']
+        ruby-version: ['3.4', '4.0.2']
     steps:
     - uses: actions/checkout@v4
     - name: Set up Ruby
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c6861c7..281a106 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 * [#48](https://github.com/dblock/fui/pull/48): Fixed `NameError: undefined local variable or method 'project_path'` in verbose mode - [@dblock](https://github.com/dblock).
 * [#49](https://github.com/dblock/fui/pull/49): Added summary output to `find` command: prints `Found N unused header(s).` or `No unused imports found.` - [@dblock](https://github.com/dblock).
 * [#50](https://github.com/dblock/fui/pull/50): Fixed `delete` command to also remove `.mm` (Objective-C++) implementation files - [@dblock](https://github.com/dblock).
+* [#51](https://github.com/dblock/fui/pull/51): Added support for Ruby 4.x - [@dblock](https://github.com/dblock).
 * Your contribution here.
 
 ### 0.5.0 (2018/12/19)
diff --git a/Gemfile b/Gemfile
index 23f16df..c5dc6c7 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,5 +7,5 @@ gem 'danger-changelog'
 gem 'danger-pr-comment', '0.1.0'
 gem 'danger-toc'
 gem 'rake'
-gem 'rspec', '~> 3.4.0'
+gem 'rspec', '~> 3.13'
 gem 'rubocop', '1.86.1'