Colson Baker (born April 22, 1990), known professionally as Machine Gun Kelly (MGK, stylized in all lowercase), is an American rapper, singer, songwriter, and actor.

MGK released four mixtapes from 2007 to 2010 before he signed with Puff Daddy's Bad Boy Records, an imprint of Interscope Records the following year. His debut studio album, Lace Up (2012), peaked at number four on the US Billboard 200 and was led by the single "Wild Boy" (featuring Waka Flocka Flame), which marked his first entry on the Billboard Hot 100 and received triple platinum certification by the Recording Industry Association of America (RIAA). His second and third albums, General Admission (2015) and Bloom (2017), were both met with critical praise and similar commercial success; the latter was supported by the single "Bad Things" (with Camila Cabello), which peaked at number four on the Billboard Hot 100. His 2018 single, "Rap Devil", was a diss track aimed at fellow rapper Eminem, and peaked at number 13 on the chart despite mixed critical response. His fourth album, Hotel Diablo (2019), experimented with rap rock and saw a critical incline.

MGK's fifth album, Tickets to My Downfall (2020), saw a complete departure from hip-hop in favor of a pop-punk sound and aesthetic, with its production entirely helmed by Blink-182 drummer Travis Barker. It debuted atop the Billboard 200—becoming the only rock album to do so that year—and was supported by the single "My Ex's Best Friend" (featuring blackbear), which peaked within the top 20 of the Billboard Hot 100. Its sequel, Mainstream Sellout (2022), served as his sixth album and matched its commercial success, although critical reception was mixed.

MGK had his first starring role in the romantic drama Beyond the Lights (2014), and since appeared in the techno-thriller Nerve (2016), the horror Bird Box (2018), the comedy Big Time Adolescence and portrayed Tommy Lee in the Mötley Crüe biopic The Dirt (both 2019). In 2022, he and Mod Sun made their directorial debuts with the stoner comedy film Good Mourning, which they also wrote, produced, and starred in.