Glastonbury Festival (formally Glastonbury Festival of Contemporary Performing Arts and known colloquially as Glasto) is a five-day festival of contemporary performing arts held near Pilton, Somerset, England, in most summers. In addition to contemporary music, the festival hosts dance, comedy, theatre, circus, cabaret, and other arts. Leading pop and rock artists have headlined, alongside thousands of others appearing on smaller stages and performance areas. Films and albums have been recorded at the festival, and it receives extensive television and newspaper coverage.

Glastonbury takes place on 1500 acres of farmland and is attended by around 200,000 people, requiring extensive security, transport, water, and electricity-supply infrastructure. While the number of attendees is sometimes swollen by gatecrashers, a record of 300,000 people was set at the 1994 festival, headlined by the Levellers, who performed on The Pyramid Stage. Most festival staff are unpaid volunteers, helping the festival to raise millions of pounds for charity organisations.

Regarded as a major event in British culture, the festival is inspired by the ethos of the hippie, the counterculture of the 1960s, and the free festival movement. Vestiges of these traditions are retained in the Green Fields area, which includes sections known as the Green Futures, the Stone Circle and Healing Field. Michael Eavis hosted the first festival, then called Pilton Festival, after seeing an open-air Led Zeppelin concert in 1970 at the Bath Festival of Blues and Progressive Music.