diff --git a/netbox/tenancy/api/serializers_/contacts.py b/netbox/tenancy/api/serializers_/contacts.py
index ff08f4e15..a5c4dd741 100644
--- a/netbox/tenancy/api/serializers_/contacts.py
+++ b/netbox/tenancy/api/serializers_/contacts.py
@@ -3,7 +3,7 @@ from drf_spectacular.types import OpenApiTypes
 from drf_spectacular.utils import extend_schema_field
 from rest_framework import serializers
 
-from netbox.api.fields import ChoiceField, ContentTypeField
+from netbox.api.fields import ChoiceField, ContentTypeField, SerializedPKRelatedField
 from netbox.api.serializers import NestedGroupModelSerializer, NetBoxModelSerializer
 from tenancy.choices import ContactPriorityChoices
 from tenancy.models import ContactAssignment, Contact, ContactGroup, ContactRole
@@ -43,7 +43,12 @@ class ContactRoleSerializer(NetBoxModelSerializer):
 
 
 class ContactSerializer(NetBoxModelSerializer):
-    groups = ContactGroupSerializer(many=True, nested=True, required=False, allow_null=True, default=None)
+    groups = SerializedPKRelatedField(
+        queryset=ContactGroup.objects.all(),
+        serializer=ContactGroupSerializer,
+        required=False,
+        many=True
+    )
 
     class Meta:
         model = Contact
diff --git a/netbox/tenancy/tests/test_api.py b/netbox/tenancy/tests/test_api.py
index 26132a752..04ac3078c 100644
--- a/netbox/tenancy/tests/test_api.py
+++ b/netbox/tenancy/tests/test_api.py
@@ -170,7 +170,7 @@ class ContactTest(APIViewTestCases.APIViewTestCase):
     model = Contact
     brief_fields = ['description', 'display', 'id', 'name', 'url']
     bulk_update_data = {
-        'groups': None,
+        'groups': [],
         'comments': 'New comments',
     }
 
@@ -195,11 +195,9 @@ class ContactTest(APIViewTestCases.APIViewTestCase):
         cls.create_data = [
             {
                 'name': 'Contact 4',
-                'groups': [contact_groups[1].pk],
             },
             {
                 'name': 'Contact 5',
-                'groups': [contact_groups[1].pk],
             },
             {
                 'name': 'Contact 6',