Easter Vigil, also called the Paschal Vigil or the Great Vigil of Easter, is a service held in traditional Christian churches as the first official celebration of the Resurrection of Jesus. Historically, it is during this service that people are baptized and that adult catechumens are received into full communion with the Church. It is held in the hours of darkness between sunset on Holy Saturday and sunrise on Easter Day – most commonly in the evening of Holy Saturday or midnight – and is the first celebration of Easter, days traditionally being considered to begin at sunset.
Among liturgical western churches including the Roman Catholic Church, the Anglican Communion, and Lutheran churches, the Easter Vigil is the most important service of public worship and Masses of the liturgical year, marked by the first use since the beginning of Lent of the exclamatory "Alleluia", a distinctive feature of the Easter season.
In Eastern Orthodox churches, Oriental Orthodox churches, and other traditions of Eastern Christianity, the extremely festive ceremonies and Divine Liturgy which are celebrated during the Easter Vigil are unique to that night and are the most elaborate and important of the liturgical year.