The difference in Christmas dates between countries is primarily due to churches following different liturgical calendars. Some churches continue to use the Julian calendar, while others use the Revised Julian or Gregorian calendar. Because the Julian calendar is currently 13 days behind the Gregorian calendar, churches that still follow it celebrate Christmas on 7 January, which corresponds to 25 December on the Julian calendar.

December 25th -

• Roman Catholic Church
• Maronite Church
• Chaldean Catholic Church
• Syriac Catholic Church
• Armenian Catholic Church (most dioceses)
• Melkite Greek Catholic Church (many dioceses)
• Assyrian Church of the East
• Ancient Church of the East
• Syriac Orthodox Church
• Greek Orthodox Church
• Romanian Orthodox Church
• Bulgarian Orthodox Church
• Cypriot Orthodox Church
• Albanian Orthodox Church
• Orthodox Church of Ukraine
• Czech & Slovak Orthodox Church
• Constantinople (Ecumenical Patriarchate)

January 6th -

• Armenian Apostolic Church

January 7th -

• Russian Orthodox Church
• Serbian Orthodox Church
• Georgian Orthodox Church
• Ukrainian Orthodox
• Orthodox Church of Jerusalem (Patriarchate of Jerusalem)
• Mount Athos monasteries
• Coptic Orthodox Church (Egypt)
• Ethiopian Orthodox Tewahedo Church
• Eritrean Orthodox Tewahedo Church
• Ukrainian Greek Catholic Church (some parishes)
• Melkite Greek Catholic Church (some parishes)
• Ruthenian Greek Catholic Church (some parishes)