Mart Seim (born 24 October 1990) is an Estonian weightlifter competing in the +105 kg category.
Seim competed for Estonia at the 2014 World Weightlifting Championships finishing 4th with a total of 431 kg.
At the 2015 World Weightlifting Championships he finished third at the men's +105 kg.
After Aleksey Lovchev failed doping tests, Seim was promoted to second place (Silver), and Georgian Lasha Talakhadze to Gold.Seim's father and grandfather were also weightlifters.