William McNamara (9 June 1876 – 21 November 1959) was an Australian rules footballer who played for Carlton in the Victorian Football League (VFL). McNamara was a wingman at Carlton for six seasons and left the club after not being picked for the 1904 finals. As a result, he missed out on playing in the successful team which won three successive premierships from 1906 to 1908. During this time he was instead a VFL umpire and officiated in 104 games, mostly as a boundary umpire. He was on the boundary in the 1910 VFL Grand Final.