Mr. Big was an American rock band formed in Los Angeles in 1988. The band was originally composed of Eric Martin (lead vocals), Paul Gilbert (guitar), Billy Sheehan (bass), and Pat Torpey (drums). Though primarily a hard rock band, they are also known for softer songs. Their songs are often marked by strong vocals and vocal harmonies. Their hits include "To Be with You" (a number-one single in 15 countries in 1992) and "Just Take My Heart". The band takes its name from a song by Free which it covered on the 1993 album Bump Ahead.

Mr. Big remained active and popular for over a decade despite internal conflicts and changing musical trends, releasing four studio albums: Mr. Big (1989), Lean into It (1991), Bump Ahead (1993) and Hey Man (1996). Guitarist Paul Gilbert departed the band in 1999, and Richie Kotzen was brought on as a guitarist and vocalist. The band released two more albums with this line-up: Get Over It (1999) and Actual Size (2001). Mr. Big disbanded in 2002.

Following requests from fans, Mr. Big reunited with its original line-up in 2009. The band's first post-reunion tour was in Japan. In 2010, Mr. Big released its first album in 15 years with the same line-up: What If.... During the recording of the follow-up album ...The Stories We Could Tell (2014), Pat Torpey was diagnosed with Parkinson's disease and participated only marginally as a touring support. The band's ninth album, Defying Gravity (2017), was its last record involving Torpey, who performed on select tracks and was credited as a "drum producer"; drummer Matt Starr performed a majority of the drums on the album in his place. Following Torpey's death in 2018, the band went on hiatus, and later conducted a farewell tour in 2023 with former Spock's Beard dummer/vocalist Nick D'Virgilio. D'Virgilio subsequently performed on the band's tenth and final album Ten (2024).

Mr. Big is frequently cited as an example of the "Big in Japan" phenomenon, where a musical act is disproportionately more popular in Japan compared to similar groups. Mr. Big are sometimes labeled as a one-hit wonder for "To Be with You", but they have maintained consistent popularity in the Japanese market throughout their career.