Luka Mesec (born 1 July 1987) is a Slovenian politician and activist who has been the leader of the eco-socialist The Left party since June 2017.
Mesec was elected to the Slovenian National Assembly for the first time at the 2014 parliamentary election, and reelected at the 2018 parliamentary election.
He is the coordinator of the Council of the Initiative for Democratic Socialism, Labour-punk University and its successor, the Institute for Labour Studies.