diff --git a/package_manager/src/ProcessFactory.php b/package_manager/src/ProcessFactory.php
index d7089d80dc2f24fe2c83a69eb5f8fca9307b5637..6d7ef4c90aa305b7d341752f61d9517a7f7e3e77 100644
--- a/package_manager/src/ProcessFactory.php
+++ b/package_manager/src/ProcessFactory.php
@@ -75,7 +75,7 @@ final class ProcessFactory implements ProcessFactoryInterface {
       $env['COMPOSER_HOME'] = $this->getComposerHomePath();
     }
     // Ensure that the PHP interpreter is in the PATH.
-    $env['PATH'] = $this->getEnv('PATH') . ':' . static::getPhpDirectory();
+    $env['PATH'] = static::getPhpDirectory() . ':' . $this->getEnv('PATH');
     return $process->setEnv($env);
   }