One Direction (commonly abbreviated as 1D) are an English-Irish pop boy band based in London, composed of Niall Horan, Liam Payne, Harry Styles, Louis Tomlinson, and previously, Zayn Malik until his departure from the band on 25 March 2015.

The group signed with Simon Cowell's record label Syco Records after forming and finishing third in the seventh series of the British televised singing competition The X Factor in 2010. Propelled to international success by social media, One Direction's four albums, Up All Night (2011), Take Me Home (2012), Midnight Memories (2013) and Four (2014) topped charts in most major markets, and generated hit singles including "What Makes You Beautiful", "Live While We're Young", "Story of My Life" and "Steal My Girl".

Their achievements include five Brit Awards, four MTV Video Music Awards, eleven MTV Europe Music Awards, and nineteen Teen Choice Awards out of nineteen nominations, among many others. According to Nick Gatfield, the chairman and chief executive of Sony Music Entertainment UK, One Direction represented a $50 million business empire by June 2012. They were proclaimed 2012's "Top New Artist" by Billboard. According to the Sunday Times Rich List, by April 2013, they had an estimated personal combined wealth of £25 million ($41.2m) making them the second-wealthiest musicians in the UK under 30 years of age. In 2014, Forbes listed them the second-highest earning celebrities under 30, with the group earning an estimated $75 million from June 2013 to June 2014.

After the release of Four, One Direction became the first band in the U.S. Billboard 200 history to have their first four albums debut at number one. Their third album, Midnight Memories, was the biggest-selling album worldwide of 2013 despite being released in late November. In 2014, Billboard named One Direction Artist of the Year. The band will temporarily go on hiatus in March 2016 following their fifth album for a year to pursue solo careers.