core/lib/Drupal/Core/Entity/Entity.php |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/core/lib/Drupal/Core/Entity/Entity.php b/core/lib/Drupal/Core/Entity/Entity.php
index 2c2eec0..b1cbe7d 100644
--- a/core/lib/Drupal/Core/Entity/Entity.php
+++ b/core/lib/Drupal/Core/Entity/Entity.php
@@ -651,9 +651,11 @@ public function relatedEntities() {
 
     // Gather a list of related entities.
     foreach ($this->getProperties() as $name => $definition) {
-      $field_item = $this->get($name)->offsetGet(0);
-      if ($field_item instanceof EntityReferenceItem && $entity = $field_item->entity) {
-        $relationships[] = $entity;
+      $field_items = $this->get($name);
+      foreach ($field_items as $offset => $field_item) {
+        if ($field_item instanceof EntityReferenceItem && $entity = $field_item->entity) {
+          $relationships[] = $entity;
+        }
       }
     }