Robert "Robbie" "Mad Dog" Muir (born 8 October 1953) is a former Indigenous Australian rules football player for the St Kilda Football Club in the Victorian Football League (VFL).
Recruited from the Ballarat Football League, he played 68 games over 7 interrupted seasons (between 1974–1984) as a brilliant player who was notorious for angry outbursts on the field. He was reported 13 times, and suspended for 22 weeks – including 12 weeks after a match against Carlton in 1984.
In 2006 Muir became involved in umpiring in an amateur league which was notorious for its players who disrespected officials. With Muir, a fearsome player, as umpire it was believed his intimidatory presence might help stamp out this behaviour. He also umpired the EJ Whitten Legends Game in 2006, as well as the "Barristers v Solicitors" charity game at Glenferrie Oval on 25 June 2006.