William McMaster (24 December 1811 – 22 September 1887) was a Canadian wholesaler, senator and banker in the 19th century.

He also helped found McMaster University in Toronto (later moved to Hamilton), Ontario.

Born in County Tyrone, Northern Ireland, McMaster migrated to York, Upper Canada, (now Toronto) in 1833.

As a member of Bond Street Baptist Church, McMaster helped to finance its building of larger facilities at Jarvis Street Baptist Church.

Through his wife, financing was also provided for the Hospital for Sick Children in Toronto.