Moulthun Ly (born 20 November 1991) is an Australian chess player.

[3] Ly picked up his first GM norm by winning the Sydney International Chess Open in 2014 with a score of 7.0/9.

[2][5] In 2020, he won the 54th Begonia Open on tie-breaks from Mark Chapman, Zong-Yuan Zhao and Jesse Jager.

[7][8] He is the founder and editor of 50 Moves Magazine, a chess magazine which he operates with contributions from leading Australian players such as fellow Australian grandmasters Ian Rogers and Max Illingworth.

[9] Ly is currently the Head of Online Learning at Australian Junior Chess on Cloud,[10] and publishes videos weekly on Molton, his personal YouTube channel.