Eid al-Fitr occurs on the first day of which Islamic month?

Eid al-Fitr occurs on the first day of the Islamic month of Shawwal.

Shawwal is the tenth month of the Hijri, or Islamic, calendar. It begins immediately after Ramadan, so Eid al-Fitr marks both the conclusion of the month-long dawn-to-dusk fast and the opening of a new lunar month. The holiday date is fixed as 1 Shawwal in the Islamic calendar.

Because the Hijri calendar is lunar, Shawwal begins about 10 to 12 days earlier in the Gregorian calendar each solar year. The precise civil date can differ between countries and communities because authorities may use local crescent-moon sightings, calculated calendars, or another accepted announcement.

Ramadan is therefore the month that ends immediately before Eid al-Fitr, not the month in which the festival begins. Shawwal lasts either 29 or 30 days. Some Muslims observe six optional fasts during Shawwal, but fasting is prohibited on the first day, Eid al-Fitr itself.