Clannad (Irish pronunciation: ) are an Irish band formed in 1970 in Gweedore, County Donegal by siblings Ciarán, Pól, and Moya Brennan and their twin uncles Noel and Pádraig Duggan. They have adopted various musical styles throughout their history, including folk, folk rock, traditional Irish, Celtic and new-age music, often incorporating elements of smooth jazz and Gregorian chant.

Initially known as Clann as Dobhar, they shortened their name to Clannad in 1973 after winning the Letterkenny Folk Festival with the song "Liza". By 1979, they had released three albums and completed a successful US tour. From 1980 to 1982, they operated as a six-piece with their sister/niece Enya Brennan on additional keyboards and vocals, before she left the group to pursue a solo career. Later in 1982, Clannad gained international attention with their single "Theme from Harry's Game", which became a top-five hit in Ireland and the UK. The song was featured on Magical Ring (1983), which was met with much acclaim. They experimented with more new-age and pop-influenced sounds in the 1980s and 1990s, as evident on Macalla (1985), and Anam (1990). This transition would ultimately go on to define their sound as almost purely 'Celtic', making them innovators of that genre. After Landmarks (1997), the band went on a hiatus in order to pursue solo projects. They regrouped in 2007 as a four piece again, with Moya, Ciarán, Noel, and Pádraig completing a world tour in 2008. In 2013, Pól rejoined and they released Nádúr, their first studio album in fifteen years. Pádraig Duggan died in 2016, leaving the group to embark on their 2020 farewell tour as a quartet.

Clannad have won numerous awards throughout their career, including a Grammy Award, a BAFTA, an Ivor Novello Award, and a Billboard Music Award. They have recorded in six different languages, and scored eight UK top 10 albums. They are widely regarded as a band that have brought Irish music and the Irish language to a wider audience, often experiencing more popularity abroad than in their native Ireland.

Clannad was formed in 1970 by siblings Ciarán Brennan, Pól, and Máire Brennan and their twin uncles Noel and Pádraig Duggan. The five grew up in Dore, an area of Gweedore, a remote parish in County Donegal in the northwest corner of Ireland. It is a Gaeltacht region where Irish is the main spoken language. Raised as a Roman Catholic family of musicians, the Brennans' mother, Máire "Baba" Brennan (née Duggan), was a music teacher while their father, Leo Brennan, was a member of the Slieve Foy Band, an Irish showband. Later in their careers the two bought and ran Leo's Tavern, a pub in nearby Meenaleck where the Duggan and Brennan children would perform covers of songs by the Beatles, the Beach Boys, and Joni Mitchell.