Osamah Ali Almarwai (Arabic: أسامة علي المروعي, born on April 11, 1992) is a Yemeni submission grappler and Brazilian jiu-jitsu black belt competitor.

[1] At 19 he moved back to Saudi Arabia and continued training BJJ with coaches, Mohammed Al Dabbas, and Gerardo Dudamell, who awarded him his purple belt.

In 2019, Almarwai attended an ADCC Submission Grappling training camp which persuaded him to move to California and join Atos Jiu-Jitsu under BJJ legend André Galvão.

In 2019, Almarwai started competing in IBJJF competitions in the brown belt division,[3] winning silver in 2020 at the Pan No-Gi Championship.

[6] Almarwai faced Mikey Musumeci for the ONE Flyweight Submission Grappling World Championship at ONE Fight Night 10 on May 5, 2023.