Saudi Arabia announced on Tuesday evening that Thursday, May 17 will be the first day of Ramadan.
During Ramadan, Muslims abstain from food, drinks and sexual intercourse from dawn to dusk, which is an exercise in self-restraint, intended to bring the faithful closer to God.
The UAE, Bahrain, Egypt, Lebanon, Jordan, Iraq and Morocco were among the Arab countries that also declared the start of Ramadan on Thursday.
Internationally, Muslims in the United Kingdom, the United States, Malaysia, Australia, South Korea, Japan and Singapore will also begin fasting on Thursday.
Fasting the month of Ramadan is also one of the five pillars of Islam. It is followed by the Eid al-Fitr holiday.
As Muslims follow a lunar calendar, Eid al-Fitr starts when the new moon is spotted in the sky.
The celebrations begin when the fasting month of Ramadan ends and the following month of Shawwal begins.