Mr. Big is a hard rock group that formed in 1988. The band is a quartet composed of Eric Martin (vocals), Paul Gilbert (guitar), Billy Sheehan (bass), and Pat Torpey (drums); Mr Big also included Richie Kotzen, a reputable blues-based guitarist who replaced Gilbert in 1999. The band is noted especially for their musicianship, and scored a number of hits. Their songs were often marked by strong vocals and vocal harmonies. Their hits include "To Be With You" (Billboard Hot 100 number one single in 15 countries for weeks, in 1991) and "Green-Tinted Sixties Mind".

Mr Big have remained active and popular for over two decades, despite internal conflicts and changing music trends. They broke up in 2002, but after requests from fans reunited in 2009; their first tour was in Japan, in June 2009.

After bass player Billy Sheehan left David Lee Roth in 1988, he began piecing together a new band with the help of Mike Varney from Shrapnel Records, a label specialized in the shredding genre. He recruited Eric Martin, of the rock-oriented Eric Martin Band and also soul-leaning solo artist, and soon thereafter added guitarist Gilbert and drummer Torpey. Gilbert was already a well-respected guitarist who had released two albums with his Los Angeles-based band Racer X. Torpey came to California from Arizona, and toured with a number of high-profile artists, most notably Robert Plant.

The newly formed band hired Herbie Herbert, the former manager of Journey, Europe, and Santana, to be their manager. By 1989, they signed with Atlantic Records and released their self-titled debut the same year. The record did not gain the band a mainstream rock audience stateside, but was a success in Japan. In June 1990, the group toured in America opening for Rush.

Mr Big's second album, 1991's Lean Into It, was a major commercial breakthrough, especially two ballads, "To Be with You" (number one song in fifteen countries) and "Just Take My Heart", and "Green-Tinted Sixties Mind". They toured the UK in April and May 1991 and again in 1992, releasing a live album, Mr. Big Live, in 1992. For three nights, they opened for Aerosmith at London's Wembley Arena.

In 1993, another ballad, a cover of Cat Stevens' "Wild World", (from their third album, Bump Ahead) peaked at #27 on the Billboard Hot 100. The band also contributed the soundtrack to the Sega Mega CD release of The Amazing Spider-Man vs. The Kingpin.

They released Hey Man in 1995. The song "Take Cover" was included on the soundtrack to the cartoon series Mega Man.

Gilbert left the band in 1997, and eventually reformed Racer X. Richie Kotzen, another Shrapnel artist and former guitarist for Poison, was brought in as a guitar player. Two studio albums were released by this lineup: Get Over It in 2000, and Actual Size in 2001. Get Over It was released on September 1999, in Japan, and yielded "Superfantastic," a multi-platinum number one hit in Japan. Mr Big performed a twenty-date tour of Japan followed by a New Year's Eve 1999 show with Aerosmith at the Tokyo Dome in Tokyo. Get Over It' was released in the US in March 2000, followed by a short club stint at "Roxy", California.

In 2001, Mr Big released Actual Size in Asia. The CD sat on the charts in the number three spot and "Shine", the first single, was number one. The song was also used as the ending theme for the animation series Hellsing.

However, tension had developed between Billy Sheehan and the other members, and the band broke up in 2002.