Alan Mackay-Sim AM (born 16 May 1951) is an Australian biomedical scientist specialising in adult stem cell research, and winner of the 2017 Australian of the Year. Some of his research focuses on olfactory ensheathing cells, which are cells in the human nose that interact with the nervous system to cause a sense of smell. His research into stem cells contributed to the treatment of spinal cord injuries. The restoration of mobility to Darek Fidyka, a Polish paraplegic man, used research by Mackay-Sim. Mackay-Sim received his PhD from Macquarie University in 1980, then subsequently studied at the University of Pennsylvania and the University of Wyoming. He was the director of the National Centre for Adult Stem Cell Research at Griffith University before his retirement in 2015.