diff -u b/core/modules/text/src/Plugin/Field/FieldType/TextItem.php b/core/modules/text/src/Plugin/Field/FieldType/TextItem.php
--- b/core/modules/text/src/Plugin/Field/FieldType/TextItem.php
+++ b/core/modules/text/src/Plugin/Field/FieldType/TextItem.php
@@ -57,14 +57,30 @@
     $constraint_manager = \Drupal::typedDataManager()->getValidationConstraintManager();
     $constraints = parent::getConstraints();
 
+    $constraint_values = [];
     if ($max_length = $this->getSetting('max_length')) {
-      $constraints[] = $constraint_manager->create('ComplexData', [
-        'value' => [
-          'Length' => [
-            'max' => $max_length,
-            'maxMessage' => t('%name: the text may not be longer than @max characters.', ['%name' => $this->getFieldDefinition()->getLabel(), '@max' => $max_length]),
+      $constraint_values[] = [
+        'Length' => [
+          'max' => $max_length,
+          'maxMessage' => t('%name: the text may not be longer than @max characters.', ['%name' => $this->getFieldDefinition()->getLabel(), '@max' => $max_length,]),
+        ],
+      ];
+    }
+
+    if ($formats = $this::getParent()->getSetting('allowed_formats')) {
+      $constraint_values[] = [
+        'format' => [
+          'AllowedValues' => [
+            'choices' => $formats,
+            'choicesMessage' => t('%name: the selected format is not one the allowed formats.', ['%name' => $this->getFieldDefinition()->getLabel(),])
           ],
         ],
+      ];
+    }
+
+    if (!empty($constraint_values)) {
+      $constraints[] = $constraint_manager->create('ComplexData', [
+        'value' => $constraint_values,
       ]);
     }