Jacob Constantinou is an British MMA fighter. A native of England and son of an English father and a Polish mother, he not only competes in amateur MMA fights, but also coaches in his gym, the Leicester Shootfighters. He is a well travelled man, having visited most of North America, Asia and Europe including his mother's city, Gdańsk in Poland.

In 2015 Constantinou has been chosen to represent Team UK in the 2015 IMMAF Amateur MMA Championships in the Welterweight Division (170 lbs). After submitting his first two opponents, both in first round, Constantinou lost a unanimous decision (3x29-28) to the eventual golden medal winner, William Starks, in semifinals. Under original IMMAF rules that would make him eligible to compete for the bronze medal against the loser of the other semifinal (Polish grappler Patryk Ruta). Due to an on-the-fly change of the ruling, both of the semi finals losers have been awarded bronze medals in all the weight categories, making Constantinou a bronze medallist.