Section 25 were formed in Blackpool, Lancashire, United Kingdom in November 1977. Initially they were a duo, consisting of brothers Larry Cassidy (bass, vocals) and Vincent Cassidy (drums). In June 1978 they made their live debut, and in November were joined by guitarist Paul Wiggin.

Their debut 7", "Girls Don't Count", was released in 1980 on Factory Records, produced by Ian Curtis and Rob Gretton of Joy Division. All Section 25 releases would be released through Factory Records. Their debut LP, Always Now, was released in 1981 and produced by Martin Hannett.

The three-piece group played many gigs in Britain and Northern Europe between 1979 and 1981, both as a headline act and with other Factory Records artists, such as Joy Division, A Certain Ratio, The Durutti Column, Crispy Ambulance and New Order. The group also released a self-produced second album, The Key of Dreams. However the original line-up split in 1982 when Paul Wiggin declined to fly to the United States for their first North American tour.

Joined by percussionist Lee Shallcross, Section 25 gradually evolved a more electronic-dance direction, a process which culminated in the album From The Hip and single Looking From a Hilltop, both released in 1984 and produced by Bernard Sumner of New Order. This new version of the band also featured Angela Flowers (vocals, keyboards) and Jenny Ross (vocals, keyboards). This line-up completed a second tour of North America in 1985.

In 1986 the group again splintered, leaving husband-and-wife team Larry Cassidy and Jenny Ross to complete a fourth album, Love and Hate, finally released by Factory in 1988. Section 25 then fell silent for more than a decade, although their entire catalogue was reissued on CD on LTM as well as an archive DVD.

In 2001 the band regrouped and wrote new material. It is expected that this will form the basis for a new album in 2006, although without Jenny Ross who died in 2004. Now with Ian Butterworth (ex of fellow Factory act Tunnelvison) on guitar and Roger Wikeley on bass and keyboards the band performed their first live show in nearly two decades at their hometown Poulton-Le-Fylde in May 2006 followed by dates in Blackpool, Paris, Brussels and Leicester. Larry and Vin Cassidy also feature in the 2006 Factory documentary film Shadowplayers.