diff --git a/__tests__/tools.test.ts b/__tests__/tools.test.ts
index 41799e8f..0873f1bf 100644
--- a/__tests__/tools.test.ts
+++ b/__tests__/tools.test.ts
@@ -367,7 +367,7 @@ describe('Tools tests', () => {
 
   it('checking addTools on linux', async () => {
     const script: string = await tools.addTools(
-      'cs2pr, php-cs-fixer, phpstan, phpunit, pecl, phinx, phinx:1.2.3, phive, php-config, phpize, symfony, wp-cli',
+      'cs2pr, flex, php-cs-fixer, phpstan, phpunit, pecl, phinx, phinx:1.2.3, phive, php-config, phpize, symfony, wp-cli',
       '7.4',
       'linux'
     );
@@ -396,6 +396,7 @@ describe('Tools tests', () => {
       'add_tool https://github.com/wp-cli/builds/blob/gh-pages/phar/wp-cli.phar?raw=true wp-cli'
     );
     expect(script).toContain('add_pecl');
+    expect(script).toContain('add_composer_tool flex flex symfony/');
     expect(script).toContain('add_composer_tool phinx phinx robmorgan/');
     expect(script).toContain('add_composer_tool phinx phinx:1.2.3 robmorgan/');
     expect(script).toContain('add_devtools');
@@ -404,7 +405,7 @@ describe('Tools tests', () => {
   });
   it('checking addTools on darwin', async () => {
     const script: string = await tools.addTools(
-      'phpcs, phpcbf, phpcpd, phpmd, psalm, phinx, phive:1.2.3, cs2pr:1.2.3, composer-prefetcher:1.2.3, phpize, php-config, symfony, symfony:1.2.3, wp-cli',
+      'flex, phpcs, phpcbf, phpcpd, phpmd, psalm, phinx, phive:1.2.3, cs2pr:1.2.3, composer-prefetcher:1.2.3, phpize, php-config, symfony, symfony:1.2.3, wp-cli',
       '7.4',
       'darwin'
     );
@@ -429,6 +430,7 @@ describe('Tools tests', () => {
     expect(script).toContain(
       'https://github.com/vimeo/psalm/releases/latest/download/psalm.phar psalm'
     );
+    expect(script).toContain('add_composer_tool flex flex symfony/');
     expect(script).toContain('add_composer_tool phinx phinx robmorgan/');
     expect(script).toContain(
       'add_tool https://github.com/phar-io/phive/releases/download/1.2.3/phive-1.2.3.phar phive'
@@ -450,7 +452,7 @@ describe('Tools tests', () => {
   });
   it('checking addTools on windows', async () => {
     const script: string = await tools.addTools(
-      'codeception, cs2pr, deployer, prestissimo, phpmd, phinx, phive:0.13.2, php-config, phpize, symfony, wp-cli, does_not_exit',
+      'codeception, cs2pr, deployer, flex, prestissimo, phpmd, phinx, phive:0.13.2, php-config, phpize, symfony, wp-cli, does_not_exit',
       '7.4',
       'win32'
     );
@@ -460,6 +462,7 @@ describe('Tools tests', () => {
     expect(script).toContain(
       'Add-Tool https://github.com/staabm/annotate-pull-request-from-checkstyle/releases/latest/download/cs2pr cs2pr'
     );
+    expect(script).toContain('Add-Composer-Tool flex flex symfony/');
     expect(script).toContain(
       'Add-Tool https://deployer.org/deployer.phar deployer'
     );
diff --git a/dist/index.js b/dist/index.js
index 4d004016..92687e63 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -2042,6 +2042,9 @@ function addTools(tools_csv, php_version, os_version) {
                         url = yield getDeployerUrl(version);
                         script += yield addArchive(tool, version, url, os_version);
                         break;
+                    case 'flex':
+                        script += yield addPackage(tool, release, 'symfony/', os_version);
+                        break;
                     case 'phinx':
                         script += yield addPackage(tool, release, 'robmorgan/', os_version);
                         break;
diff --git a/src/tools.ts b/src/tools.ts
index ff211583..3e7e2137 100644
--- a/src/tools.ts
+++ b/src/tools.ts
@@ -517,6 +517,9 @@ export async function addTools(
         url = await getDeployerUrl(version);
         script += await addArchive(tool, version, url, os_version);
         break;
+      case 'flex':
+        script += await addPackage(tool, release, 'symfony/', os_version);
+        break;
       case 'phinx':
         script += await addPackage(tool, release, 'robmorgan/', os_version);
         break;