diff --git a/src/Extension/CoreExtension.php b/src/Extension/CoreExtension.php
index 6ac3610813..5c4087ec21 100644
--- a/src/Extension/CoreExtension.php
+++ b/src/Extension/CoreExtension.php
@@ -1329,6 +1329,10 @@ function twig_constant($constant, $object = null)
         $constant = \get_class($object).'::'.$constant;
     }
 
+    if (!\defined($constant)) {
+        throw new RuntimeError(sprintf('Constant "%s" is undefined.', $constant));
+    }
+
     return \constant($constant);
 }