A1 (stylised as a1) are an English-Norwegian pop group that formed in 1998. The line-up consists of Christian Ingebrigtsen, Mark Read and Ben Adams. Paul Marazzi was originally a member from 1998 until his departure in 2002. Ingebrigtsen is originally from Oslo, Norway, but the other members originate from London, England.

Their first single, "Be the First to Believe", entered the UK Singles Chart at number six in mid-1999. They achieved success in the UK and other parts of the world in the late 1990s and early 2000s, particularly South East Asia and Japan. In the UK, they scored two number ones and eight top 10 hits, seven of which were written by the band. Adding to this, they also won a BRIT Award for "British Breakthrough Act" in 2001. They were managed by band manager Tim Byrne, who also formed Steps.