diff --git a/core/lib/Drupal/Core/Field/BaseFieldDefinition.php b/core/lib/Drupal/Core/Field/BaseFieldDefinition.php
index 16df7c6..25df63b 100644
--- a/core/lib/Drupal/Core/Field/BaseFieldDefinition.php
+++ b/core/lib/Drupal/Core/Field/BaseFieldDefinition.php
@@ -545,6 +545,12 @@ public function getInitialValue() {
    * @return $this
    */
   public function setInitialValue($value) {
+    // @todo Implement initial value support for multi-value fields in
+    //   https://www.drupal.org/node/2883851.
+    if ($this->isMultiple()) {
+      throw new FieldException('Multi-value fields can not have an initial value.');
+    }
+
     if ($value === NULL) {
       $value = [];
     }