diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6fd8b1b..a9695fc 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -9,8 +9,9 @@ jobs:
     strategy:
       matrix:
         PHP_VERSION: [ '8.1', '8.3', '8.4' ]
+        OS: [ubuntu-latest, ubuntu-24.04]
     name: Test Apache action
-    runs-on: ubuntu-latest
+    runs-on:  ${{ matrix.OS }}
     steps:
       - name: Create fake site
         run: |
@@ -23,6 +24,11 @@ jobs:
         uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.PHP_VERSION }}
+          extensions: :xdebug
+      - name: Ensure Xdebug is not running
+        run: |
+          php -m
+          php -r "if (extension_loaded('xdebug')) trigger_error('xdebug on', E_USER_ERROR);"
       - uses: actions/checkout@v2
       - name: Setup Apache
         uses: ./
@@ -33,3 +39,41 @@ jobs:
       - name: Test fake site
         run: |
           curl -sSf http://127.0.0.1:9090
+      - name: Ensure Xdebug is not running
+        run: |
+          php -m
+          php -r "if (extension_loaded('xdebug')) trigger_error('xdebug on', E_USER_ERROR);"
+  test-with-xdebug:
+    name: Test Apache action
+    runs-on:  ubuntu-latest
+    steps:
+      - name: Create fake site
+        run: |
+          mkdir /tmp/sut
+          echo '<?php' | sudo tee /tmp/sut/index.php
+          echo '  $text = "It works!";' | sudo tee -a /tmp/sut/index.php
+          echo '  print "<strong>$text</strong>";' | sudo tee -a /tmp/sut/index.php
+        shell: bash
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 8.4
+          extensions: xdebug
+      - name: Ensure Xdebug is running
+        run: |
+          php -m
+          php -r "if (!extension_loaded('xdebug')) trigger_error('xdebug on', E_USER_ERROR);"
+      - uses: actions/checkout@v2
+      - name: Setup Apache
+        uses: ./
+        with:
+          php-version: 8.4
+          site-directory: /tmp/sut
+          http-port: 9090
+      - name: Test fake site
+        run: |
+          curl -sSf http://127.0.0.1:9090
+      - name: Ensure Xdebug is running
+        run: |
+          php -m
+          php -r "if (!extension_loaded('xdebug')) trigger_error('xdebug on', E_USER_ERROR);"
diff --git a/action.yml b/action.yml
index 552cc8a..601b7bb 100644
--- a/action.yml
+++ b/action.yml
@@ -12,15 +12,22 @@ inputs:
     default: 8888\
 # Install Apache and configure to serve the site under test. Apache is run
 # in the foreground using the same user as the test runner to avoid common
-# pitfalls with file ownership.
+# pitfalls with file ownership. This action also disables xdebug if it has
+# resulted in it being installed.
 runs:
   using: "composite"
   steps:
     - name: Install Apache with mod_php
       run: |
+        WAS_XDEBUG_INSTALLED=`php -r "echo extension_loaded('xdebug');"`
         LC_ALL=C.UTF-8 sudo apt-add-repository http://ppa.launchpad.net/ondrej/php/ubuntu
         sudo apt install libapache2-mod-php${{ inputs.php-version }}
         sudo a2enmod php${{ inputs.php-version }} rewrite
+        IS_XDEBUG_INSTALLED=`php -r "echo extension_loaded('xdebug');"`
+        if [[ "$IS_XDEBUG_INSTALLED" == "1" && "$WAS_XDEBUG_INSTALLED" != "1" ]]; then
+          echo "Disabling Xdebug"
+          sudo phpdismod xdebug
+        fi;
       shell: bash
     - name: Configure the site under test
       run: |