Sir William Lawrence Bragg, CH, OBE, MC, FRS (31 March 1890 – 1 July 1971) was an English physicist who shared the Nobel Prize in Physics in 1915 with his father Sir William Henry Bragg. He was the director of the Cavendish Laboratory, Cambridge when the epochal discovery of the structure of DNA was made by James Watson and Francis Crick in February 1953.