Harry "Rat" Westwick (April 23, 1876 – April 3, 1957) was a Canadian athlete in ice hockey and lacrosse.
Westwick, nicknamed the Rat by a journalist, is most noted for his play with the Ottawa Hockey Club, nicknamed the Silver Seven during his day which won and defended the Stanley Cup from 1903 until 1906.
He was a member of the Ottawa Capitals lacrosse team from 1896 until 1904, winning three championships.
His brother Tom was also a professional ice hockey player.