William Rioli (born 4 June 1995) is a professional Australian rules footballer playing for the West Coast Eagles in the Australian Football League (AFL).
He was drafted by the West Coast Eagles with their third selection and fifty-second overall in the 2016 national draft.
He made his debut in the fifty-one point win against the Western Bulldogs at Etihad Stadium in the round two of the 2018 season.
Coming from the Rioli family, which has a long history in VFL/AFL football, he is the cousin of Dean Rioli (Essendon Football Club), Cyril Rioli (Hawthorn Football Club) and Ronnie Burns (from his mother's side), uncle of current Richmond Football Club player Daniel Rioli and the nephew of Maurice Rioli.In September 2019 he received an indefinite provisional suspension under the AFL and ASADA anti-doping code for an alleged adverse analytical finding for urine substitution.
Rioli was subsequently ruled out from competing with the West Coast in that year's finals series.