diff --git a/rest_framework/schemas/openapi.py b/rest_framework/schemas/openapi.py
index 4bd1b31e4..74969ceb8 100644
--- a/rest_framework/schemas/openapi.py
+++ b/rest_framework/schemas/openapi.py
@@ -263,7 +263,7 @@ class AutoSchema(ViewInspector):
         if isinstance(field, serializers.ManyRelatedField):
             return {
                 'type': 'array',
-                'items': self._map_field(field.child_relation)
+                'items': self._map_field(method, field.child_relation)
             }
         if isinstance(field, serializers.PrimaryKeyRelatedField):
             model = getattr(field.queryset, 'model', None)
diff --git a/tests/schemas/test_openapi.py b/tests/schemas/test_openapi.py
index 8e7dffc5e..ef4fee651 100644
--- a/tests/schemas/test_openapi.py
+++ b/tests/schemas/test_openapi.py
@@ -18,6 +18,21 @@ from rest_framework.schemas.openapi import (
 from . import views
 
 
+class ExampleModel(models.Model):
+    text = models.TextField()
+
+
+class ExampleSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ExampleModel
+        fields = ['id', 'text']
+
+
+class ExampleViewSet(viewsets.ModelViewSet):
+    serializer_class = ExampleSerializer
+    queryset = ExampleModel.objects.none()
+
+
 def create_request(path):
     factory = RequestFactory()
     request = Request(factory.get(path))
@@ -50,11 +65,15 @@ class TestBasics(TestCase):
 class TestFieldMapping(TestCase):
     def test_list_field_mapping(self):
         inspector = AutoSchema()
+        inspector.init(ComponentRegistry())
+
         cases = [
             (serializers.ListField(), {'items': {}, 'type': 'array'}),
             (serializers.ListField(child=serializers.BooleanField()), {'items': {'type': 'boolean'}, 'type': 'array'}),
             (serializers.ListField(child=serializers.FloatField()), {'items': {'type': 'number'}, 'type': 'array'}),
             (serializers.ListField(child=serializers.CharField()), {'items': {'type': 'string'}, 'type': 'array'}),
+            (serializers.ManyRelatedField(child_relation=ExampleSerializer(), read_only=True),
+             {'items': {'$ref': '#/components/schemas/Example', 'type': 'object'}, 'type': 'array'}),
             (serializers.ListField(child=serializers.IntegerField(max_value=4294967295)),
              {'items': {'type': 'integer', 'format': 'int64'}, 'type': 'array'}),
             (serializers.IntegerField(min_value=2147483648),
@@ -682,18 +701,6 @@ class TestOperationIntrospection(TestCase):
         assert 'format' not in properties['ip']
 
     def test_modelviewset(self):
-        class ExampleModel(models.Model):
-            text = models.TextField()
-
-        class ExampleSerializer(serializers.ModelSerializer):
-            class Meta:
-                model = ExampleModel
-                fields = ['id', 'text']
-
-        class ExampleViewSet(viewsets.ModelViewSet):
-            serializer_class = ExampleSerializer
-            queryset = ExampleModel.objects.none()
-
         router = routers.DefaultRouter()
         router.register(r'example', ExampleViewSet)