Michael David Watt (born December 20, 1957) is an American bassist, vocalist and songwriter. He co-founded and played bass guitar for the rock bands Minutemen (1980–1985), Dos (1985–present), and Firehose (1986–1994). He began a solo career with the 1995 album Ball-Hog or Tugboat? and has since released three additional solo albums, most recently in 2010 with Hyphenated-man. He is also the frontman for the supergroup Big Walnuts Yonder (2008–present), a member of the art rock group Banyan (1997–present) and is involved with several other musical projects. From 2003 until 2013, he was the bass guitarist for The Stooges.

Watt has been called "one of the greatest bassists on the planet". CMJ New Music called Watt a "seminal post-punk bass player". Readers of NME voted Mike Watt one of the "40 Greatest Bassists of All Time" and LA Weekly awarded him the number six spot in "The 20 Best Bassists of All Time". In November 2008, Watt received the Bass Player Magazine lifetime achievement award, presented by Flea. The Red Hot Chili Peppers dedicated their best-selling album, 1991's Blood Sugar Sex Magik, to Watt.

Watt was born in Portsmouth, Virginia. His father was a machinist's mate in the Navy and when he was young, Watt's family moved to San Pedro, California, where he became good friends with D. Boon. Watt and Boon picked up bass and guitar, respectively. Watt was a fan of T. Rex and Blue Öyster Cult, while Boon's exposure to rock music was limited to Creedence Clearwater Revival, another Watt favorite.

In 1978, Watt and Boon formed a band called The Reactionaries with drummer George Hurley and vocalist Martin Tamburovich. The band later became Minutemen with another drummer named Frank Tonche, who only lasted two shows with the group; Hurley, who had been in the short-lived new wave group Hey Taxi! at the time Minutemen first formed, rejoined Watt and Boon. After signing with SST Records in 1980, Minutemen began touring constantly, releasing a number of albums along the way. Their music was based on the speed, brevity, and intensity of punk, but included elements of jazz, folk, and funk.

Born with Osgood–Schlatter disease, Watt had surgeries on both knees in the early 1980s which limited touring in 1981. Watt wrote all of the music for What Makes a Man Start Fires? as he was laid up after one of his knee surgeries, living with his mother at the time and needed to keep himself occupied.

In 1984, Watt met Black Flag bassist Kira Roessler during a Black Flag/Minutemen tour. They soon became romantically involved, and subsequently began collaborating on songs, including material on Minutemen's final album 3-Way Tie (For Last). They also formed a two-bass duo, Dos, and have since recorded and released three records.

Minutemen ended tragically on December 22, 1985, when Boon was killed in an automobile crash at the age of 27 while driving to Arizona with his girlfriend. Their fifth full-length album, 3-Way Tie (For Last), had already been scheduled for release at the time of the accident. In the documentary film We Jam Econo, Watt mentioned that the last time he saw Boon, he had received lyrics for 10 songs from critic and songwriter Richard Meltzer for a planned collaboration with Minutemen. Minutemen were also planning to record a triple album with the working title 3 Dudes, 6 Sides, 3 Studio, 3 Live as way to counteract bootleggers.

After Boon's death, Watt was profoundly depressed; he and Hurley initially intended to quit music altogether. Sonic Youth invited Watt to hang out with them in New York City in 1986; they recorded a cover of Madonna's "Burnin' Up" (with additional guitars by Greg Ginn) on the first Ciccone Youth EP, and Watt played bass for two songs on the Sonic Youth album Evol. Watt cites this period as critical in inspiring his post-Minutemen career saying, "The first thing I did was Thurston asked me to play bass on Evol. That was a big highlight, man. Like, 'What, you want me to play without D. Boon?'"