Christmas Eve is the evening or entire day before Christmas Day, the festival commemorating the birth of Jesus. Christmas Day is observed around the world, and Christmas Eve is widely observed as a full or partial holiday in anticipation of Christmas Day. Together, both days are considered one of the most culturally significant celebrations in Christendom and Western society.

The observance of Christmas around the world varies by country. The day of Christmas, and in some cases the day before and the day after, are recognized by many national governments and cultures worldwide, including in areas where Christianity is a minority religion. In some non-Christian areas, periods of former colonial rule introduced the celebration ; in others, Christian minorities or foreign cultural influences have led populations to observe the holiday.