diff --git a/Config/Parser/YamlParser.php b/Config/Parser/YamlParser.php
index 7b4f73dcd..3b43b8277 100644
--- a/Config/Parser/YamlParser.php
+++ b/Config/Parser/YamlParser.php
@@ -7,6 +7,7 @@
 use Symfony\Component\DependencyInjection\Exception\InvalidArgumentException;
 use Symfony\Component\Yaml\Exception\ParseException;
 use Symfony\Component\Yaml\Parser;
+use Symfony\Component\Yaml\Yaml;
 
 class YamlParser implements ParserInterface
 {
@@ -24,7 +25,7 @@ public static function parse(\SplFileInfo $file, ContainerBuilder $container)
         $container->addResource(new FileResource($file->getRealPath()));
 
         try {
-            $typesConfig = self::$yamlParser->parse(file_get_contents($file->getPathname()));
+            $typesConfig = self::$yamlParser->parse(file_get_contents($file->getPathname()), Yaml::PARSE_CONSTANT);
         } catch (ParseException $e) {
             throw new InvalidArgumentException(sprintf('The file "%s" does not contain valid YAML.', $file), 0, $e);
         }
diff --git a/Resources/doc/definitions/type-system/enum.md b/Resources/doc/definitions/type-system/enum.md
index 66d1d3172..5cfe26ab3 100644
--- a/Resources/doc/definitions/type-system/enum.md
+++ b/Resources/doc/definitions/type-system/enum.md
@@ -12,7 +12,8 @@ Episode:
         description: "One of the films in the Star Wars Trilogy"
         values:
             NEWHOPE:
-                value: 4
+                # We can use a PHP constant
+                value: !php/const App\StarWars\Movies::MOVIE_NEWHOPE
                 description: "Released in 1977."
                 # to deprecate a value, only set the deprecation reason
                 #deprecationReason: "Just because"
diff --git a/Tests/Config/Parser/Constant.php b/Tests/Config/Parser/Constant.php
new file mode 100644
index 000000000..d38f51962
--- /dev/null
+++ b/Tests/Config/Parser/Constant.php
@@ -0,0 +1,8 @@
+<?php
+
+namespace Overblog\GraphQLBundle\Tests\Config\Parser;
+
+class Constant
+{
+    const CONSTANT = 1;
+}
diff --git a/Tests/Config/Parser/YamlParserTest.php b/Tests/Config/Parser/YamlParserTest.php
new file mode 100644
index 000000000..a4ab7735d
--- /dev/null
+++ b/Tests/Config/Parser/YamlParserTest.php
@@ -0,0 +1,52 @@
+<?php
+
+namespace Overblog\GraphQLBundle\Tests\Config\Parser;
+
+use Overblog\GraphQLBundle\Config\Parser\YamlParser;
+use Symfony\Bundle\FrameworkBundle\Tests\TestCase;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Exception\InvalidArgumentException;
+
+class YamlParserTest extends TestCase
+{
+    /** @var ContainerBuilder|\PHPUnit_Framework_MockObject_MockObject */
+    private $containerBuilder;
+
+    public function setUp()
+    {
+        $this->containerBuilder = $this->getMockBuilder(ContainerBuilder::class)->setMethods(['addResource'])->getMock();
+    }
+
+    public function testParseEmptyFile()
+    {
+        $fileName = __DIR__.'/fixtures/yml/empty.yml';
+
+        $this->assertContainerAddFileToResources($fileName);
+
+        $config = YamlParser::parse(new \SplFileInfo($fileName), $this->containerBuilder);
+        $this->assertEquals([], $config);
+    }
+
+    public function testParseInvalidFile()
+    {
+        $fileName = __DIR__.'/fixtures/yml/invalid.yml';
+        file_put_contents($fileName, iconv('UTF-8', 'ISO-8859-1', "not_utf-8: 'äöüß'"));
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage(sprintf('The file "%s" does not contain valid YAML.', $fileName));
+        YamlParser::parse(new \SplFileInfo($fileName), $this->containerBuilder);
+    }
+
+    public function testParseConstant()
+    {
+        $expected = ['values' => ['constant' => Constant::CONSTANT]];
+        $actual = YamlParser::parse(new \SplFileInfo(__DIR__.'/fixtures/yml/constant.yml'), $this->containerBuilder);
+        $this->assertEquals($expected, $actual);
+    }
+
+    private function assertContainerAddFileToResources($fileName)
+    {
+        $this->containerBuilder->expects($this->once())
+            ->method('addResource')
+            ->with($fileName);
+    }
+}
diff --git a/Tests/Config/Parser/fixtures/yml/constant.yml b/Tests/Config/Parser/fixtures/yml/constant.yml
new file mode 100644
index 000000000..4971b7e2d
--- /dev/null
+++ b/Tests/Config/Parser/fixtures/yml/constant.yml
@@ -0,0 +1,2 @@
+values:
+    constant: !php/const Overblog\GraphQLBundle\Tests\Config\Parser\Constant::CONSTANT
\ No newline at end of file
diff --git a/Tests/Config/Parser/fixtures/yml/empty.yml b/Tests/Config/Parser/fixtures/yml/empty.yml
new file mode 100644
index 000000000..e69de29bb
diff --git a/Tests/Config/Parser/fixtures/yml/invalid.yml b/Tests/Config/Parser/fixtures/yml/invalid.yml
new file mode 100644
index 000000000..1f7c66feb
--- /dev/null
+++ b/Tests/Config/Parser/fixtures/yml/invalid.yml
@@ -0,0 +1 @@
+not_utf-8: 'äöüß'
\ No newline at end of file