Sir Henry Peter Francis Swinnerton-Dyer, 16th Baronet, KBE, FRS (2 August 1927 – 26 December 2018) was an English mathematician specialising in number theory at the University of Cambridge.

As a mathematician he was best known for his part in the Birch and Swinnerton-Dyer conjecture relating algebraic properties of elliptic curves to special values of L-functions, which was developed with Bryan Birch during the first half of the 1960s with the help of machine computation, and for his work on the Titan operating system.

[2] Swinnerton-Dyer was the son of Sir Leonard Schroeder Swinnerton Dyer, 15th Baronet, and his wife Barbara, daughter of Hereward Brackenbury.

He was educated at the Dragon School in Oxford, Eton College and Trinity College, Cambridge, where he was supervised by J. E. Littlewood, and spent a year abroad as a Commonwealth Fund Fellow at the University of Chicago.

[3] He was later made a Fellow of Trinity, and was Master of St Catharine's College from 1973 to 1983 and vice-chancellor of the University of Cambridge from 1979 to 1981.