Christmas is an annual festival commemorating the birth of Jesus Christ, observed primarily on December 25 as a religious and cultural celebration among billions of people around the world. A feast central to the liturgical year in Christianity, it follows the season of Advent or the Nativity Fast, and initiates the season of Christmastide, which historically in the West lasts twelve days and culminates on Twelfth Night. Christmas Day is a public holiday in many countries, is celebrated religiously by a majority of Christians, as well as culturally by many non-Christians, and forms an integral part of the holiday season surrounding it.

The nativity of Jesus, nativity of Christ, birth of Jesus or birth of Christ is documented in the biblical gospels of Luke and Matthew. The two accounts agree that Jesus was born in Bethlehem, Judaea, that his mother, Mary, was engaged to a man named Joseph, who was descended from King David and was not his biological father, and that his birth was caused by divine intervention. Some scholars do not see the two canonical gospel nativity stories as historically factual since they present clashing accounts and irreconcilable genealogies. The secular history of the time does not synchronize with the narratives of the birth and early childhood of Jesus in the two gospels. Some view the question of historicity as secondary, given that gospels were primarily written as theological documents rather than chronological timelines.