diff --git a/CHANGES/plugin_api/domain-get-create-serializer-mixin.bugfix b/CHANGES/plugin_api/domain-get-create-serializer-mixin.bugfix
new file mode 100644
index 0000000000..43a8c62c84
--- /dev/null
+++ b/CHANGES/plugin_api/domain-get-create-serializer-mixin.bugfix
@@ -0,0 +1 @@
+Fixed `GetOrCreateSerializerMixin` not accepting pulp_domain for the natural key creation.
diff --git a/pulpcore/app/serializers/base.py b/pulpcore/app/serializers/base.py
index 446576afbb..fc47468e6d 100644
--- a/pulpcore/app/serializers/base.py
+++ b/pulpcore/app/serializers/base.py
@@ -386,6 +386,8 @@ def get_or_create(cls, natural_key, default_values=None):
             if default_values:
                 data.update(default_values)
             data.update(natural_key)
+            if "pulp_domain" in natural_key:
+                del data["pulp_domain"]
             serializer = cls(data=data)
             try:
                 serializer.is_valid(raise_exception=True)
@@ -402,6 +404,8 @@ def get_or_create(cls, natural_key, default_values=None):
                 # validation failed with 400 'unique' error code only
                 result = cls.Meta.model.objects.get(**natural_key)
             try:
+                if "pulp_domain" in natural_key:
+                    serializer.validated_data["pulp_domain"] = natural_key["pulp_domain"]
                 result = result or serializer.create(serializer.validated_data)
             except IntegrityError:
                 # recover from a race condition, where another thread just created the object
diff --git a/pulpcore/tests/unit/serializers/test_base.py b/pulpcore/tests/unit/serializers/test_base.py
index f7ae0b8768..54fccf7095 100644
--- a/pulpcore/tests/unit/serializers/test_base.py
+++ b/pulpcore/tests/unit/serializers/test_base.py
@@ -1,8 +1,15 @@
 import pytest
 
+from django.test import TestCase
 from rest_framework import serializers
 
-from pulpcore.app.serializers import validate_unknown_fields
+from pulpcore.app.serializers import (
+    validate_unknown_fields,
+    RBACContentGuardSerializer,
+    GetOrCreateSerializerMixin,
+)
+from pulpcore.app.models import RBACContentGuard
+from pulpcore.app.util import get_domain
 
 
 def test_unknown_field():
@@ -108,3 +115,28 @@ def test_ignored_fields_no_side_effects():
     initial_data = {"field1": 1, "csrfmiddlewaretoken": 2}
     defined_fields = {"field1": 1}
     validate_unknown_fields(initial_data, defined_fields)
+
+
+@pytest.fixture
+def guard_fixture(db):
+    return RBACContentGuard.objects.get_or_create(name="test")[0]
+
+
+class GuardSerializer(GetOrCreateSerializerMixin, RBACContentGuardSerializer):
+    pass
+
+
+def test_mixin_get(guard_fixture):
+    """Test GetOrCreateSerializerMixin's get functionality."""
+    natural_key = {"name": "test", "pulp_domain": get_domain()}
+    guard = GuardSerializer.get_or_create(natural_key)
+    assert guard.pk == guard_fixture.pk
+
+
+def test_mixin_create(guard_fixture):
+    """Test GetOrCreateSerializerMixin's create functionality.'"""
+    natural_key = {"name": "test2", "pulp_domain": get_domain()}
+    default_data = {"description": "hello"}
+    guard = GuardSerializer.get_or_create(natural_key, default_data)
+    assert guard.pk != guard_fixture.pk
+    assert guard.description == default_data["description"]