The 12 Days of Christmas fall between two major Christian feasts: the Nativity on Christmas Day and Epiphany, which is celebrated on January 6; in the U.S. Catholic Church, Epiphany is celebrated on the Sunday after January 6 at Mass. The 12 Days build on the Octave of Christmas, which ends on the Solemnity of Mary, Mother of God (New Year’s Day).
Tradition also holds that it likely took the Three Kings, or “Magi,” twelve days to journey to baby Jesus. Jesus, the Son of God, was revealed to them when they arrived. We celebrate this revelation on Epiphany.
12 Days of Christmas in the Catholic Church. The 12 days include the feasts associated with the Octave and four additional celebratory days. In 2022-2023, the liturgical season of Christmas extends another three days until the Sunday after Epiphany, January 8, 2023.
The first day of Christmas is the Nativity of the Lord.