diff --git a/core/lib/Drupal/Core/Template/Attribute.php b/core/lib/Drupal/Core/Template/Attribute.php
index 633bd8c8daa..f67a982f224 100644
--- a/core/lib/Drupal/Core/Template/Attribute.php
+++ b/core/lib/Drupal/Core/Template/Attribute.php
@@ -200,11 +200,15 @@ public function removeAttribute() {
       // Support arrays or multiple arguments.
       if (is_array($arg)) {
         foreach ($arg as $value) {
-          unset($this[$value]);
+          if (isset($this[$value])) {
+            unset($this[$value]);
+          }
         }
       }
       else {
-        unset($this[$arg]);
+        if (isset($this[$arg])) {
+          unset($this[$arg]);
+        }
       }
     }