Eid al-Fitr is the earlier of the two official holidays celebrated within Islam. Eid al-Fitr is celebrated by Muslims worldwide because it marks the end of the month-long dawn-to-sunset fasting of Ramadan. Eid al-Fitr falls on the first day of Shawwal in the Islamic calendar; this does not always fall on the same Gregorian day, as the start of any lunar Hijri month varies based on when the new moon is sighted by local religious authorities. The holiday is known under various other names in different languages and countries around the world. The day is also called "Lesser Eid", or simply Eid.

There are two official holidays in Islam that are celebrated by Muslims worldwide: Eid al-Fitr and Eid al-Adha. The timing of both holidays are set by the lunar Islamic calendar, which is based upon the cycle of the moon, and so is different from the more common, European, solar-based Gregorian calendar. Every year, the Gregorian dates of the Islamic holidays change.