Not A Single Doubt (1 October 2001 – 27 June 2022) was an Australian thoroughbred racehorse and successful stallion, having sired over 70 individual stakes winners.

On the strength of these performances, Not A Single Doubt started a short priced favourite for the 2YO Magic Millions Classic however ran second behind that seasons Australian Champion Two Year Old, Dance Hero.

Not A Single Doubt's campaign was cut short after the Todman Stakes due to a soft tissue injury in his off-fore leg and he would not race again for another ten months.

Majority owner John Messara explained, “We would like to make a stallion out of Not A Single Doubt, he is a speed horse, we believe Victoria offers an excellent suite of sprint races in the autumn."

Messara stated, "Not A Single Doubt is a wonderful story for Arrowfield and for many breeders, owners, buyers and trainers, rising from the bottom of our roster to become one of Australia’s most popular and successful stallions.