Chemistry is the third studio album by English-Irish girl group Girls Aloud. It was released in the United Kingdom on 5 December 2005 by Polydor Records. After the success of What Will the Neighbours Say?, the album was again entirely produced by Brian Higgins and his production team Xenomania. Chemistry is a loose concept album which details celebrity lifestyle and "what it's like to be a twentysomething girl in London." A number of the songs avert the verse-chorus form typical of pop music.

Chemistry was universally acclaimed by a number of contemporary music critics upon its release. Despite a relatively low chart position (peaking at 11, the lowest charting release by the group), the album yielded four top ten singles and was certified platinum in the United Kingdom and Ireland, selling over 390,000 copies. The album was followed by the Chemistry Tour, which had Girls Aloud performing in arenas for the first time.