Laurence Joseph Mullen Jr. (; born 31 October 1961) is an Irish musician, best known as the drummer and co-founder of the rock band U2. A member of the band since its inception, he has recorded 15 studio albums with U2. Mullen's distinctive, almost military drumming style developed from his playing martial beats in childhood marching bands.

Mullen was born in Dublin, where he attended Mount Temple Comprehensive School. In 1976, he co-founded U2 after posting a message on the school's notice board in search of musicians. Mullen has worked on numerous side projects during his career. In 1990, he produced the Ireland national football team's song "Put 'Em Under Pressure" for the 1990 FIFA World Cup. In 1996, he worked with U2 bandmate Adam Clayton on a dance re-recording of the "Theme from Mission: Impossible". He has also collaborated with musicians such as Maria McKee, Nanci Griffith, Emmylou Harris, and Alice Cooper. Mullen has sporadically acted in films, most notably in Man on the Train (2011) and A Thousand Times Good Night (2013).

Mullen has received 22 Grammy Awards and has been inducted into the Rock and Roll Hall of Fame. In 2016, Rolling Stone ranked Mullen the 96th-greatest drummer of all time.