McWilliam is a surname. Notable people with the surname include:
Candia McWilliam (born 1955), Scottish writer Colin McWilliam (1928–1989), Scottish academic and writer F. E. McWilliam (1909–1992), British sculptor George McWilliam (1878–1968), Australian rules footballer George Roy McWilliam (1905–1977), Canadian politician James Ormiston McWilliam (1808–1862), Scottish naval surgeon, physician, and writer John McWilliam (1941–2009), Scottish politician Michael McWilliam (born 1933), British banker, academic administrator, and historian Peter McWilliam (1879–1951), Scottish footballer Richard McWilliam (1953–2013), American businessman