Yes, Elf on the Shelf does leave on Christmas Eve. It is customary for the Elf on the Shelf to leave the family's home on Christmas Eve, so that they can return to the North Pole to report back to Santa on how the children have been behaving throughout the year. The Elf on the Shelf leaves a special note for the family, explaining that they will return the next Christmas and reminding the children to be on their best behavior!