diff --git a/modules/openapi-generator/src/main/resources/python/rest.mustache b/modules/openapi-generator/src/main/resources/python/rest.mustache
index 98f2c502a91d..772efe91b39f 100644
--- a/modules/openapi-generator/src/main/resources/python/rest.mustache
+++ b/modules/openapi-generator/src/main/resources/python/rest.mustache
@@ -181,7 +181,7 @@ class RESTClientObject(object):
                 # Pass a `string` parameter directly in the body to support
                 # other content types than Json when `body` argument is
                 # provided in serialized form
-                elif isinstance(body, str):
+                elif isinstance(body, str) or isinstance(body, bytes):
                     request_body = body
                     r = self.pool_manager.request(
                         method, url,
diff --git a/samples/client/petstore/python/petstore_api/rest.py b/samples/client/petstore/python/petstore_api/rest.py
index e1e032711e74..6ce51c7c316d 100644
--- a/samples/client/petstore/python/petstore_api/rest.py
+++ b/samples/client/petstore/python/petstore_api/rest.py
@@ -189,7 +189,7 @@ class RESTClientObject(object):
                 # Pass a `string` parameter directly in the body to support
                 # other content types than Json when `body` argument is
                 # provided in serialized form
-                elif isinstance(body, str):
+                elif isinstance(body, str) or isinstance(body, bytes):
                     request_body = body
                     r = self.pool_manager.request(
                         method, url,
diff --git a/samples/openapi3/client/petstore/python/petstore_api/rest.py b/samples/openapi3/client/petstore/python/petstore_api/rest.py
index e1e032711e74..6ce51c7c316d 100644
--- a/samples/openapi3/client/petstore/python/petstore_api/rest.py
+++ b/samples/openapi3/client/petstore/python/petstore_api/rest.py
@@ -189,7 +189,7 @@ class RESTClientObject(object):
                 # Pass a `string` parameter directly in the body to support
                 # other content types than Json when `body` argument is
                 # provided in serialized form
-                elif isinstance(body, str):
+                elif isinstance(body, str) or isinstance(body, bytes):
                     request_body = body
                     r = self.pool_manager.request(
                         method, url,