Girls Aloud are a British pop girl group that was created through the ITV talent show Popstars: The Rivals in 2002. The line up consisted of members Cheryl Tweedy, Nadine Coyle, Sarah Harding, Nicola Roberts and Kimberley Walsh. In 2012, the group was named as the United Kingdom's biggest selling girl group of the 21st century so far, with over 4.3 million singles sales and 4 million albums sold in the UK alone. During their two decades together, the group achieved a string of twenty top ten singles on the UK Singles Chart, including four number ones. They also achieved seven certified albums, two of which debut at number one. They have been nominated for five Brit Awards, winning the 2009 Best Single for "The Promise".

A girl group is a music act featuring several female singers who generally harmonize together. The term "girl group" is also used in a narrower sense in the United States to denote the wave of American female pop music singing groups, many of whom were influenced by doo-wop and which flourished in the late 1950s and early 1960s between the decline of early rock and roll and start of the British Invasion. All-female bands, in which members also play instruments, are usually considered a separate phenomenon. These groups are sometimes called "girl bands" to differentiate, although this terminology is not universally followed.