Overthorpe is a heritage-listed former residence and grounds and now multi-unit residential complex and grounds at 337-347 New South Head Road, Double Bay, Municipality of Woollahra, New South Wales, Australia. It was built from 1900 to 1906. It is also known as part of the former Sir John Hay's garden. The property is privately owned. It was added to the New South Wales State Heritage Register on 2 April 1999.