WOW! is the fourth album released in September 1987 by Bananarama. It is entirely produced and co-written with the Stock Aitken Waterman production trio and is the last album by the girl group to generate significant chart hits in the U.S. Tensions between group member Siobhan Fahey and Stock, Aitken and Waterman regarding songwriting input and lyrical content (particularly with the track "Strike it Rich"[citation needed]) prompted Fahey's departure from Bananarama months after its release. By the time of the album's fourth single ("I Want You Back") Fahey had been replaced with Jacquie O'Sullivan (the single version of the song was re-recorded with O'Sullivan).
While the album was a moderate success in both the UK and US, it was a particularly big hit in Australia, where it topped the charts.