Buddha's Birthday, the birthday of the Prince Siddhartha Gautama, is a holiday traditionally celebrated in Mahayana Buddhism.

In all east Asian countries, except Japan beginning in 1873, it is held on the 8th day of the 4th month in the Chinese lunar calendar, and the day is an official holiday in Hong Kong, Macau, and South Korea. The date varies from year to year in the Gregorian calendar: