William Matthew Rigby (14 October 1923 – 2 June 2003) was an Australian politician. He was a Labor Party member of the New South Wales Legislative Assembly from 1959 to 1965, representing the electorate of Hurstville. Rigby remained involved in public life after his parliamentary defeat, serving as president of the Miscellaneous Workers' Union from 1966 to 1973. He also served for a time as a special adviser to Senator Doug McClelland, and was involved in a number of Aboriginal social welfare groups. He died in 2003.