diff --git a/rest_framework/renderers.py b/rest_framework/renderers.py
index 0a3b03729..db1fdd128 100644
--- a/rest_framework/renderers.py
+++ b/rest_framework/renderers.py
@@ -9,6 +9,7 @@ REST framework also provides an HTML renderer that renders the browsable API.
 
 import base64
 import contextlib
+import datetime
 from urllib import parse
 
 from django import forms
@@ -1062,6 +1063,7 @@ class OpenAPIRenderer(BaseRenderer):
             def ignore_aliases(self, data):
                 return True
         Dumper.add_representer(SafeString, Dumper.represent_str)
+        Dumper.add_representer(datetime.timedelta, encoders.CustomScalar.represent_timedelta)
         return yaml.dump(data, default_flow_style=False, sort_keys=False, Dumper=Dumper).encode('utf-8')
 
 
diff --git a/rest_framework/utils/encoders.py b/rest_framework/utils/encoders.py
index 35a89eb09..aa4542286 100644
--- a/rest_framework/utils/encoders.py
+++ b/rest_framework/utils/encoders.py
@@ -65,3 +65,14 @@ class JSONEncoder(json.JSONEncoder):
         elif hasattr(obj, '__iter__'):
             return tuple(item for item in obj)
         return super().default(obj)
+
+
+class CustomScalar:
+    """
+    CustomScalar that knows how to encode timedelta that renderer
+    can understand.
+    """
+    @classmethod
+    def represent_timedelta(cls, dumper, data):
+        value = str(data.total_seconds())
+        return dumper.represent_scalar('tag:yaml.org,2002:str', value)
diff --git a/tests/schemas/test_openapi.py b/tests/schemas/test_openapi.py
index 0ea6d1ff9..1eb5b84b7 100644
--- a/tests/schemas/test_openapi.py
+++ b/tests/schemas/test_openapi.py
@@ -1162,6 +1162,31 @@ class TestGenerator(TestCase):
         assert b'"openapi": "' in ret
         assert b'"default": "0.0"' in ret
 
+    def test_schema_rendering_to_yaml(self):
+        patterns = [
+            path('example/', views.ExampleGenericAPIView.as_view()),
+        ]
+        generator = SchemaGenerator(patterns=patterns)
+
+        request = create_request('/')
+        schema = generator.get_schema(request=request)
+        ret = OpenAPIRenderer().render(schema)
+        assert b"openapi: " in ret
+        assert b"default: '0.0'" in ret
+
+    def test_schema_rendering_timedelta_to_yaml_with_validator(self):
+
+        patterns = [
+            path('example/', views.ExampleValidatedAPIView.as_view()),
+        ]
+        generator = SchemaGenerator(patterns=patterns)
+
+        request = create_request('/')
+        schema = generator.get_schema(request=request)
+        ret = OpenAPIRenderer().render(schema)
+        assert b"openapi: " in ret
+        assert b"duration:\n          type: string\n          minimum: \'10.0\'\n" in ret
+
     def test_schema_with_no_paths(self):
         patterns = []
         generator = SchemaGenerator(patterns=patterns)
diff --git a/tests/schemas/views.py b/tests/schemas/views.py
index f1ed0bd4e..c08208bf2 100644
--- a/tests/schemas/views.py
+++ b/tests/schemas/views.py
@@ -134,6 +134,11 @@ class ExampleValidatedSerializer(serializers.Serializer):
     ip4 = serializers.IPAddressField(protocol='ipv4')
     ip6 = serializers.IPAddressField(protocol='ipv6')
     ip = serializers.IPAddressField()
+    duration = serializers.DurationField(
+        validators=(
+            MinValueValidator(timedelta(seconds=10)),
+        )
+    )
 
 
 class ExampleValidatedAPIView(generics.GenericAPIView):