diff --git a/bin/playwright-install b/bin/playwright-install
index 3419d63..7e7b162 100755
--- a/bin/playwright-install
+++ b/bin/playwright-install
@@ -269,8 +269,8 @@ final class PlaywrightServerInstaller
 
         return match ($packageManager) {
             'pnpm' => $hasPnpmLock
-                    ? ['pnpm', 'install', '--prod', '--frozen-lockfile']
-                    : ['pnpm', 'install', '--prod', '--no-frozen-lockfile'],
+                    ? ['pnpm', 'install', '--prod', '--frozen-lockfile', '--ignore-workspace', '--lockfile-dir', $this->serverDir]
+                    : ['pnpm', 'install', '--prod', '--no-frozen-lockfile', '--ignore-workspace', '--lockfile-dir', $this->serverDir],
             'yarn' => $hasYarnLock
                     ? ['yarn', 'install', '--production', '--frozen-lockfile']
                     : ['yarn', 'install', '--production'],
diff --git a/tests/Integration/Installer/PlaywrightInstallDependenciesTest.php b/tests/Integration/Installer/PlaywrightInstallDependenciesTest.php
new file mode 100644
index 0000000..8847066
--- /dev/null
+++ b/tests/Integration/Installer/PlaywrightInstallDependenciesTest.php
@@ -0,0 +1,121 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the community-maintained Playwright PHP project.
+ * It is not affiliated with or endorsed by Microsoft.
+ *
+ * (c) 2025-Present - Playwright PHP - https://github.com/playwright-php
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Playwright\Tests\Integration\Installer;
+
+use PHPUnit\Framework\Attributes\CoversNothing;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Process\Process;
+
+#[CoversNothing]
+final class PlaywrightInstallDependenciesTest extends TestCase
+{
+    private string $serverDir;
+
+    private string $stubBinDir;
+
+    protected function setUp(): void
+    {
+        $projectDir = \dirname(__DIR__, 3);
+
+        $sandbox = sys_get_temp_dir().'/playwright-install-'.bin2hex(random_bytes(6));
+        mkdir($sandbox, 0o777, true);
+        $sandbox = realpath($sandbox);
+
+        $this->serverDir = $sandbox.'/bin';
+        $this->stubBinDir = $sandbox.'/stub-bin';
+        mkdir($this->serverDir);
+        mkdir($this->stubBinDir);
+
+        copy($projectDir.'/bin/playwright-install', $this->serverDir.'/playwright-install');
+        copy($projectDir.'/bin/package.json', $this->serverDir.'/package.json');
+        symlink($projectDir.'/vendor', $this->serverDir.'/vendor');
+
+        $this->stubCommand('node', 'v20.0.0');
+        $this->stubCommand('npm', '10.0.0');
+        $this->stubCommand('pnpm', '10.0.0');
+    }
+
+    protected function tearDown(): void
+    {
+        $this->removeDirectory(\dirname($this->serverDir));
+    }
+
+    #[Test]
+    public function itIsolatesThePnpmInstallFromAnOuterWorkspace(): void
+    {
+        $process = $this->runInstaller();
+
+        $this->assertSame(0, $process->getExitCode(), $process->getErrorOutput());
+        $this->assertStringContainsString(
+            "'pnpm' 'install' '--prod' '--no-frozen-lockfile' '--ignore-workspace' '--lockfile-dir' '{$this->serverDir}'",
+            $process->getOutput(),
+        );
+    }
+
+    #[Test]
+    public function itIsolatesThePnpmInstallFromAnOuterWorkspaceWhenALockfileExists(): void
+    {
+        touch($this->serverDir.'/pnpm-lock.yaml');
+
+        $process = $this->runInstaller();
+
+        $this->assertSame(0, $process->getExitCode(), $process->getErrorOutput());
+        $this->assertStringContainsString(
+            "'pnpm' 'install' '--prod' '--frozen-lockfile' '--ignore-workspace' '--lockfile-dir' '{$this->serverDir}'",
+            $process->getOutput(),
+        );
+    }
+
+    private function runInstaller(string ...$arguments): Process
+    {
+        $process = new Process(
+            [\PHP_BINARY, $this->serverDir.'/playwright-install', '--dry-run', '--verbose', ...$arguments],
+            env: ['PATH' => $this->stubBinDir.\PATH_SEPARATOR.getenv('PATH')],
+        );
+        $process->run();
+
+        return $process;
+    }
+
+    private function stubCommand(string $name, string $version): void
+    {
+        $path = $this->stubBinDir.'/'.$name;
+
+        file_put_contents($path, "#!/bin/sh\necho {$version}\n");
+        \chmod($path, 0o755);
+    }
+
+    private function removeDirectory(string $directory): void
+    {
+        foreach (scandir($directory) ?: [] as $entry) {
+            if ('.' === $entry || '..' === $entry) {
+                continue;
+            }
+
+            $path = $directory.'/'.$entry;
+
+            if (is_dir($path) && !is_link($path)) {
+                $this->removeDirectory($path);
+
+                continue;
+            }
+
+            unlink($path);
+        }
+
+        rmdir($directory);
+    }
+}