diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 85fed7d..2ff0f75 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -16,7 +16,7 @@ jobs:
       - name: Install Ruby and gems
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 3.4
+          ruby-version: 4.0
           bundler-cache: true
 
       - name: Run Rubocop
@@ -27,7 +27,7 @@ jobs:
     name: Ruby ${{ matrix.ruby }} (${{ matrix.appraisal }})
     strategy:
       matrix:
-        ruby: ["3.1", "3.2", "3.3", "3.4"]
+        ruby: ["3.1", "3.2", "3.3", "3.4", "4.0"]
         appraisal: ["rails_7.1", "rails_7.2", "rails_8.0", "rails_8.1"]
         exclude:
           - ruby: "3.1"
diff --git a/.rubocop.yml b/.rubocop.yml
index d965ebb..d09b71c 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -10,7 +10,7 @@ inherit_gem:
   rubocop-shopify: rubocop.yml
 
 AllCops:
-  TargetRubyVersion: 3.4
+  TargetRubyVersion: 4.0
   TargetRailsVersion: 8.1
   NewCops: enable
   Exclude: