Christmas or Christmas Day is an annual holiday that celebrates the birth of Jesus. It is traditionally observed on December 25, though some Eastern Orthodox Churches celebrate it on January 7, which corresponds to December 25 of the Julian calendar.

The popularity of Christmas can be traced in part to its status as a winter festival. Many cultures have historically celebrated their most important holiday in winter because there is less agricultural work to do at this time. Examples of winter festivals that have influenced Christmas include the pre-Christian festivals of Yule and Saturnalia. Many of the traditions associated with the holiday have origins in these pagan winter celebrations. Various local and regional Christmas traditions are still practiced, despite the widespread influence of American, Australian, and British Christmas motifs disseminated by film, popular literature, television, and other media.