William Marshall Mason, also nicknamed "Big Willie", is a former professional rugby league footballer who played in the 2000s and 2010s. An Australia and Tonga international and New South Wales State of Origin representative forward, he played in the National Rugby League for the Canterbury-Bankstown Bulldogs, the Sydney Roosters, the North Queensland Cowboys, the Newcastle Knights and the Manly-Warringah Sea Eagles. Mason also played in the Super League for English club the Hull Kingston Rovers and French club, the Catalans Dragons. He also played rugby union in the Top 14 for French club RC Toulonnais. During his career Mason was involved in a number of controversial off-field incidents which have received media publicity due to his high profile in the NRL.

The Tonga national rugby league team represents Tonga in rugby league football. They are currently the fifth ranked team in the world. The team was formed to compete in the 1986 Pacific Cup, and have competed at six Rugby League World Cups, starting in 1995 and continuing consecutively until the most recent tournament. Their best result was at the 2017 Rugby League World Cup, where they were semi-finalists.