Saudi Arabia, Qatar and the UAE have all announced that Eid ul-Fitr will be marked on Wednesday July 6.
Authorities made the announcement on Monday evening after failing to sight the moon that marks the end of the fasting month of Ramadan.
Traditionally, it is celebrated for three days and is an official holiday in all Muslim-majority countries.
In Kenya, the government has already set aside Thursday July 7 as the official holiday to mark the event.
However, most Muslims in the country are expected to join the predominantly Muslim countries on Wednesday to mark the event.