Sir John William Simpson KBE FRIBA (9 August 1858 – 30 March 1933) was an English architect and President of the Royal Institute of British Architects from 1919 to 1921.
Simpson was the eldest son of the Brighton architect Thomas Simpson and his wife Clara Hart. He was the brother of another architect, Gilbert Murray Simpson.
He was educated privately and articled to his father in 1875, but later attended the Royal Academy Schools.
Simpson became an Associate of the Royal Institute of British Architects in 1882. He was in partnership with M. P. Manning from 1881 to 1884 and subsequently with E. J. Milner Allen, specializing in public buildings.
He was an active member of the Royal Institute of British Architects, rising to be its President, and of a number of architectural associations in other countries. He also wrote books and articles on architecture.
In 1905, he was joined in his practice by the young Maxwell Ayrton, and they entered into a partnership in 1910.
He never married, and died at home in West Hill, Highgate, Middlesex, on 30 March 1933.
Simpson wrote many professional papers on architecture and town planning. He edited the periodical The Book of Book-Plates between 1900 and 1903.
John William Simpson's entry at www.scottisharchitects.org.uk