On the First Sunday of Advent, Christians start lighting their Advent wreaths, and praying their Advent daily devotional;[2] believers may also erect their Chrismon tree,[2] light a Christingle,[3] as well as engage in other ways of preparing for Christmas, such as setting up Christmas decorations,[4][5][6] a custom that is sometimes done liturgically through a hanging of the greens ceremony.

Zechariah 9:9–10 and Matthew 21:1–9 are always read in the service, and the symbolism of the day is that Christ enters the church.

Likewise, in the Roman Rite of the Catholic Church, Advent also "begins with First Vespers (Evening Prayer I) of the Sunday that falls on or closest to 30 November and it ends before First Vespers (Evening Prayer I) of Christmas".

[10] In the Ambrosian Rite and the Mozarabic Rite, the First Sunday in Advent comes two weeks earlier than in the Roman, being on the Sunday after St. Martin's Day (11 November), six weeks before Christmas.

When Christmas Day is a Monday, Advent Sunday will fall on its latest possible date.