Grant Hayden Kenny OAM (born 14 June 1963) is an Australian former Ironman, surf lifesaver and canoeist.

Kenny made headlines in 1980 when, as a 16-year-old, he won both the Australian Junior and Open Iron Man Championship on the same day.

He also became a household name in Australia due to his sponsorship deals with Kelloggs Nutri-Grain, and appeared in television commercials for the cereal.

After turning his attention to kayaks in the mid-1980s, Kenny later became an important figure in creating the Uncle Toby's Super Series, which was a ground-breaking professional Iron Man circuit that lasted for 12 years.

Kenny was also a competitor in the first two seasons, but by 1989 his other interests had taken away the necessary time to train for such a demanding sport and his results were never anything like his domination during his late teens.