Sir William Selby Church, 1st Baronet, KCB (4 December 1837 – 28 April 1928) was a successful British physician to St Bartholomew's Hospital, president of the Royal College of Physicians from 1899 to 1905 and president of the Royal Society of Medicine from 1907 to 1909 and also in 1893 (having briefly served after the death of Sir Andrew Clark, 1st Baronet earlier that year). He is best remembered for his ability to direct policy of the associations he belonged to.