A-ha (often stylised as a-ha; Norwegian pronunciation: [ɑˈhɑː]) is a Norwegian synth-pop band formed in Oslo in 1982. Founded by Paul Waaktaar-Savoy (guitars and vocals), Magne Furuholmen (keyboards, guitars and vocals), and Morten Harket (lead vocals), the band rose to fame during the mid-1980s.

A-ha achieved their biggest success with their debut album Hunting High and Low in 1985. The album peaked at number one in their native Norway, number two in the UK, and number 15 on the US Billboard album chart; yielded the international number-one single "Take On Me", as well as "The Sun Always Shines on T.V."; and earned the band a Grammy Award nomination for Best New Artist. In the UK, Hunting High and Low continued its chart success into the following year, becoming one of the best-selling albums of 1986. The band released studio albums in 1986, 1988, and 1990, with single hits including "Hunting High and Low", "The Living Daylights", "Stay on These Roads", and "Crying in the Rain". In 1994, after their fifth studio album, Memorial Beach (1993), failed to achieve the commercial success of their previous albums, the band went on hiatus. Following a performance at the Nobel Peace Prize Concert in 1998, A-ha recorded their sixth album, 2000's Minor Earth Major Sky, which was another number-one album in Norway and Germany. This album was followed by Lifelines (2002); Analogue (2005), which was certified Silver in the UK; and Foot of the Mountain (2009), which was certified Silver in the UK and reached the top five in many European countries.

The band split after their 2010 worldwide Ending on a High Note Tour, but reunited in 2015 to release their tenth studio album, Cast in Steel. They toured in support of the album and participated at Rock in Rio, which celebrated 30 years for both the band and the event.

The band has released eleven studio albums, several compilations and four live albums, with their most recent album, True North, released on 21 October 2022. In less than a year, during 2010, the band earned an estimated 500 million Norwegian kroner from concert tickets, merchandise and the release of a greatest hits album, making them one of the 40–50 highest-grossing bands in the world. The band were listed in the Guinness World Records book for having the biggest-paying rock concert attendance; they drew an audience of 198,000 at Maracanã Stadium during the Rock in Rio festival. They have sold more than 100 million units, albums and singles combined.