Marcus Smart, American basketball player
Marcus Osmond Smart (born March 6, 1994) is an American professional basketball player for the Boston Celtics of the National Basketball Association (NBA). He played college basketball for the Oklahoma State Cowboys before being drafted with the sixth overall pick in the 2014 NBA draft.

Smart is widely considered to be one of the best defenders in the entire NBA, regardless of position, due to his fierce nature, strength, hands, and basketball IQ.