Oliver Weerasinghe (died 1980) FRIBA was a Sri Lankan architect and diplomat. He was Sri Lanka’s first City Planner  and for this reason, he his referred to as the “Father of Sri Lanka’s Town Planning”. He is a former Ambassador to the United States.
Weerasingh was educated at the Royal College Colombo and went on to study architecture at the University of Liverpool under of Sir Patrick Abercrombie. Later he became a Fellow of the Royal Institute of British Architects and a Fellow of the Royal Town Planning Institute. He was a founding President of the Ceylon Institute of Architects.
He gained wide recognition when his designed the “Lake House Building”, the head office of the Associated Newspapers of Ceylon, owned by press baron D. R. Wijewardena. He then became Ceylon’s first city planner, when he was appointed to the newly created post of Architect and City Planner of Ceylon, as the head of Ceylon’s first Department of Town and Country Planning. In this capacity he was instrumental in the planning and development of the new city of Anuradhapura in the 1940s as a step to preserving the ancient city. He headed a committee to study housing development in the island of Ceylon and its recommendations lead to the creation of the Ministry for Housing in 1954.
In 1956, he joined the United Nations and was later appointed as Sri Lanka’s Ambassador to the United States. During his tenure he established four consulates and the Buddhist Temple of Washington, D.C..
Oliver Weerasinghe married Christobel Kotalawala, the only daughter of Sir Henry Kotalawala, a member of the State Council of Ceylon from Uva and Badulla for 28 years. Their son Rohan is a Senior Managing Partner of a major law firm and daughter, Menakka, is a former lecturer at the University of Michigan.