William Michael Osborne (born 24 April 1955) is a former New Zealand rugby union player. A second five-eighth and centre, Osborne represented Wanganui and Waikato at a provincial level. Started his club career with the local Kaierau Rugby Union Club in Wanganui. He was a member of the New Zealand national side, the All Blacks, between 1975 and 1982, playing 48 matches including 16 internationals.
After retiring from playing rugby Osborne has had a successful business career, including:
He also served on the New Zealand Maori Rugby board. In 2017 he was elected vice-president of New Zealand Rugby Union, later ascending to the president's position. In 2022 he was appointed Chair of the Chiefs Rugby board.
In 2021 a new challenge trophy named after Osborne was announced for the Heartland Championship teams, to follow similar rules to the Ranfurly Shield.