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Religious festivals

Wearing costumes is an important part of holidays developed from religious festivals such as Mardi Gras (in the lead up to Easter), and Halloween (related to All Hallow's Eve). Mardi Gras costumes usually take the form of jesters and other fantasy characters; Halloween costumes traditionally take the form of supernatural creatures such as ghosts, vampires, pop-culture icons and angels.

Halloween costumes developed from pre-Christian religious traditions: to avoid being terrorized by evil spirits walking the Earth during the harvest festival Samhain, the Celts donned disguises. In the eighth century, Pope Gregory VIII designated November 1 as All Saints Day, and the preceding days as All Hallows Eve; Samhain's costuming tradition was incorporated into these Christian holidays. Given the Catholic and pagan roots of the holiday, it has been repudiated by some Protestants. However, in the modern era, Halloween "is widely celebrated in almost every corner of American life," and the wearing of costumes forms part of a secular tradition. In 2022, United States households spent an average of $100 preparing for Halloween, with $34 going to costume-related spending.

Christmas costumes typically portray characters such as Santa Claus (developed from Saint Nicholas). In Australia, the United Kingdom and the United States the American version of a Santa suit and beard is popular; in the Netherlands, the costume of Zwarte Piet is customary. Easter costumes are associated with the Easter Bunny or other animal costumes.

In Judaism, a common practice is to dress up on Purim. During this holiday, Jews celebrate the change of their destiny. They were delivered from being the victims of an evil decree against them and were instead allowed by the King to destroy their enemies. A quote from the Book of Esther, which says: "On the contrary" (Hebrew: ונהפוך הוא) is the reason that wearing a costume has become customary for this holiday.

Buddhist religious festivals in Tibet, Bhutan, Mongolia and Lhasa and Sikkim in India perform the Cham dance, which is a popular dance form utilising masks and costumes.