Woo Jin-won (Korean: 우진원, October 25, 1978), better known by his stage name Masta Wu (마스타 우), is a South Korean rapper, songwriter and producer.

[3] After being an underground rapper, Woo signed with YG Entertainment.

[6][7] He wrote several songs for his label-mates, for example project duo Hi Suhyun, solo singer Lee Hi and girl band 2NE1.

[1][8][9] As of December 2023 he has 93 songs credited to his name at the Korea Music Copyright Association.

[10] In 2016, he announced his departure from YG Entertainment to establish his own label.