diff --git a/src/Symfony/Bundle/FrameworkBundle/Test/KernelTestCase.php b/src/Symfony/Bundle/FrameworkBundle/Test/KernelTestCase.php
index 26781cdf2285c..af8f4300f2961 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Test/KernelTestCase.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Test/KernelTestCase.php
@@ -106,8 +106,9 @@ private static function getPhpUnitCliConfigArgument()
      */
     protected static function getKernelClass()
     {
-        if (isset($_SERVER['KERNEL_CLASS'])) {
-            if (!class_exists($class = $_SERVER['KERNEL_CLASS'])) {
+        if (isset($_SERVER['KERNEL_CLASS']) || isset($_ENV['KERNEL_CLASS'])) {
+            $class = isset($_SERVER['KERNEL_CLASS']) ? $_SERVER['KERNEL_CLASS'] : $_ENV['KERNEL_CLASS'];
+            if (!class_exists($class)) {
                 throw new \RuntimeException(sprintf('Class "%s" doesn\'t exist or cannot be autoloaded. Check that the KERNEL_CLASS value in phpunit.xml matches the fully-qualified class name of your Kernel or override the %s::createKernel() method.', $class, static::class));
             }