Answer
Tim Tszyu has one sibling, a brother named Nikita Tszyu. Both brothers are professional boxers and the sons of former world champion Kostya Tszyu. Nikita is the younger brother and is currently undefeated, with a record of 4-0. Tim, on the other hand, is the more accomplished boxer, with a record of 21-0 and holding the WBO Global super welterweight title.