diff --git a/src/Plugin/Validation/Constraint/ItemsCountConstraintValidator.php b/src/Plugin/Validation/Constraint/ItemsCountConstraintValidator.php
index c78f3ec..26d7625 100644
--- a/src/Plugin/Validation/Constraint/ItemsCountConstraintValidator.php
+++ b/src/Plugin/Validation/Constraint/ItemsCountConstraintValidator.php
@@ -18,7 +18,7 @@ class ItemsCountConstraintValidator extends ConstraintValidator {
       return;
     }
 
-    if ($value->get($constraint->sourceFieldName)->isEmpty()) {
+    if ($value->get($constraint->sourceFieldName)->isEmpty() && $value->getFieldDefinition($constraint->sourceFieldName)->isRequired()) {
       $this->context->addViolation($constraint->message);
     }
   }
diff --git a/tests/src/Unit/ConstraintsTest.php b/tests/src/Unit/ConstraintsTest.php
index fb1edd6..6edadda 100644
--- a/tests/src/Unit/ConstraintsTest.php
+++ b/tests/src/Unit/ConstraintsTest.php
@@ -67,6 +67,13 @@ class TestMediaEntityConstraints {
    */
   protected $sourceFields = [];
 
+  /**
+   * The source field definitions.
+   *
+   * @var array
+   */
+  protected $sourceFieldDefinitions = [];
+
   /**
    * TestMediaEntityConstraints constructor.
    *
@@ -77,6 +84,7 @@ class TestMediaEntityConstraints {
    */
   public function __construct($name, $value = NULL) {
     $this->sourceFields[$name] = new TestField($value);
+    $this->sourceFieldDefinitions[$name] = new TestFieldDefinition();
   }
 
   /**
@@ -86,6 +94,13 @@ class TestMediaEntityConstraints {
     return $this->sourceFields[$name];
   }
 
+  /**
+   * Mocks getFieldDefinition() on \Drupal\Core\Entity\FieldableEntityInterface.
+   */
+  public function getFieldDefinition($name) {
+    return $this->sourceFieldDefinitions[$name];
+  }
+
 }
 
 /**
@@ -118,3 +133,18 @@ class TestField {
   }
 
 }
+
+/**
+ * Mock class for field definitions.
+ * All test fields will be required since we're testing validation constraints.
+ */
+class TestFieldDefinition {
+
+  /**
+   * Mocks isRequired() on \Drupal\Core\Field\FieldDefinitionInterface.
+   */
+  public function isRequired() {
+    return true;
+  }
+
+}