Mötley Crüe (pronounced "motley crew") is an American heavy metal band formed in Hollywood, California, in 1981 by bassist Nikki Sixx and drummer Tommy Lee, with guitarist Mick Mars and lead vocalist Vince Neil joining right after. The band has sold over 100 million records worldwide. They have achieved seven platinum or multi-platinum certifications, nine Top 10 albums on the Billboard 200 chart (including 1989's Dr. Feelgood, which is Mötley Crüe's only studio album to reach number one), twenty-two Top 40 mainstream rock hits, and six Top 20 pop singles.

The members of Mötley Crüe are often noted for their hedonistic lifestyles and the androgynous personae they maintained. Following the hard rock and heavy metal origins on the band's first two albums, Too Fast for Love (1981) and Shout at the Devil (1983), the release of its third album Theatre of Pain (1985) saw Mötley Crüe joining the first wave of glam metal. The band employ elaborate live performances, which include flame thrower guitars, roller coaster drum kits, and the use of pyrotechnics such as fireworks and lighting Sixx on fire. Mötley Crüe's most recent studio album, Saints of Los Angeles, was released on June 24, 2008. What was planned to be the band's final show took place on New Year's Eve, December 31, 2015. The concert was filmed for a theatrical and Blu-ray release in 2016.

After two and a half years' inactivity, Neil announced in September 2018 that Mötley Crüe had reunited and was working on new material. On March 22, 2019, the band released four new songs on the soundtrack for its Netflix biopic The Dirt, based on the band's New York Times best-selling autobiography of the same name. The soundtrack went to number one on the iTunes All Genres Album Chart, number 3 on the Billboard Top Album and Digital Album sales charts, number 10 on the Billboard 200, and Top 10 worldwide. The autobiography returned to the New York Times Best Seller list at number 6 on Nonfiction Print and number 8 on Nonfiction Combined Print & E-Book. Mötley Crüe embarked on its first major tour in seven years during the summer and fall of 2022, co-headlining a North American tour with Def Leppard.

The band has experienced several lineup changes over the years, leaving Sixx as the only constant member; these included the introduction of lead vocalist John Corabi (who was Neil's replacement from 1992 to 1996) and drummer Randy Castillo, whom filled in for Lee following his departure from Mötley Crüe in 1999; he returned to the band in 2004. In October 2022, after 41 years of service, Mars announced his retirement from touring with the band, with John 5 (formerly of David Lee Roth, Marilyn Manson and Rob Zombie) replacing him.