Arkadiusz Leniart (born 20 June 1991) is a Polish chess Grandmaster (GM) (2020).

In 2006, in Herceg Novi he taking 5th place at the European Youth Chess Championship in U16 age group.

In 2006, Arkadiusz Leniart took the 3rd place in the Corus 2006 Group 1B tournament and won the second silver medal (in the colors of Polonia TradeTrans Warszawa) at the Polish Youth Team Chess Championship in Szklarska Poręba.

In 2010, he shared the 1st place (together with Marian Jurcik, Eva Repková and Robert Cvek) in the open championship of Slovakia in Banská Štiavnica.

He reached the highest rating in his career so far on December 1, 2019, with a score of 2508 points, he was then ranked 24th among Polish chess players.