Christmas Christmas, also known as Christmas Day or Christmastide, is an annual holiday falling on December 25 or January 7Some Eastern Orthodox Churches follow the traditional Julian Calendar, which is currently 13 days behind the modern Gregorian Calendar; thus, December 25 on the Julian Calendar falls on January 7 of the Greogrian Calendarreference. The Armenian Apostolic Church celebrates the Nativity of Christ on January 6, which on other Christian calendars celebrates the Epiphany.