The Twelve Days of Christmas, also known as the Twelve Days of Christmastide, are the festive Christian season celebrating the Nativity.

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.