diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index fdbe76a..d596bb7 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -14,7 +14,15 @@ jobs:
         os: [ubuntu-latest]
         php: [8.4, 8.3]
         laravel: ['11.*', '12.*', '13.*']
+        guzzle: ['7.*', '8.*']
         dependency-version: [prefer-stable]
+        exclude:
+          # laravel/framework 11.x and 12.x require guzzlehttp/guzzle ^7.8.2,
+          # so Guzzle 8 can only be tested against Laravel 13.
+          - laravel: 11.*
+            guzzle: '8.*'
+          - laravel: 12.*
+            guzzle: '8.*'
         include:
           - laravel: 11.*
             testbench: 9.*
@@ -23,17 +31,17 @@ jobs:
           - laravel: 13.*
             testbench: 11.*
 
-    name: P${{ matrix.php }} - L${{ matrix.laravel }} - ${{ matrix.dependency-version }} - ${{ matrix.os }}
+    name: P${{ matrix.php }} - L${{ matrix.laravel }} - G${{ matrix.guzzle }} - ${{ matrix.dependency-version }} - ${{ matrix.os }}
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Cache dependencies
-        uses: actions/cache@v4
+        uses: actions/cache@v6
         with:
           path: ~/.composer/cache/files
-          key: dependencies-laravel-${{ matrix.laravel }}-php-${{ matrix.php }}-composer-${{ hashFiles('composer.json') }}
+          key: dependencies-laravel-${{ matrix.laravel }}-guzzle-${{ matrix.guzzle }}-php-${{ matrix.php }}-composer-${{ hashFiles('composer.json') }}
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
@@ -44,7 +52,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          composer require "laravel/framework:${{ matrix.laravel }}" "orchestra/testbench:${{ matrix.testbench }}" --no-interaction --no-update
+          composer require "laravel/framework:${{ matrix.laravel }}" "orchestra/testbench:${{ matrix.testbench }}" "guzzlehttp/guzzle:${{ matrix.guzzle }}" --no-interaction --no-update
           composer update --${{ matrix.dependency-version }} --prefer-dist --no-interaction --no-suggest
 
       - name: Execute tests
diff --git a/composer.json b/composer.json
index 47b8f61..f410286 100644
--- a/composer.json
+++ b/composer.json
@@ -19,7 +19,7 @@
     "require": {
         "php": "^8.3",
         "illuminate/support": "^11.0|^12.0|^13.0",
-        "guzzlehttp/guzzle": "^6.5|^7.0"
+        "guzzlehttp/guzzle": "^6.5|^7.0|^8.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^11.5.3|^12.5.12",