Monsta X (Korean: 몬스타엑스; stylized in all caps) is a South Korean boy group formed through the reality survival program No.Mercy under Starship Entertainment. The group is composed of six members: Shownu, Minhyuk, Kihyun, Hyungwon, Joohoney, and I.M. Originally a seven-member group, former member Wonho left the group in October 2019.

The group debuted with their first EP Trespass on May 14, 2015. In March 2017, Monsta X released their first studio album and the final part of The Clan series The Clan Pt. 2.5: The Final Chapter. Since 2018, four of the group's Japanese singles had been certified gold by the Recording Industry Association of Japan, and since 2019, nine of the group's Korean studio albums and extended plays had been certified platinum by the Korea Music Content Association. In 2020, the group's first english-language studio album All About Luv ranked number five on the US Billboard 200 and number seven on the US Rolling Stone Top 200.

The group has been known for their "aggressive" musical style, combining elements of hip hop, EDM, and pop. With songs that are described to be "centered around loud, clattering, electronic instrumentals, vicious rap verses, and striking vocals", they have been influential across the fourth generation of K-pop, in addition to breaking gender norms in the industry before it was a trend. Throughout their career, the group has been dubbed as K-pop's "Next Generation Beastly Idols".