Marc-Antoine Olivier (born 18 June 1996) is a French competitive swimmer who specialises in long-distance open water events.
Olivier's father and brother were both swimmers, which inspired him to take up the sport as well. He began swimming when he was seven in Denain, France, and he began open-water swimming at the age of fifteen. At the 2015 World Aquatics Championships he finished 6th in the 10 km open water, which qualified him for the Olympic marathon.
He won the bronze medal in the 10 km open water marathon at the 2016 Summer Olympics, outtouching Zu Lijun of China who was recorded in the same time.