Private schools in Abu Dhabi and Dubai will reduce school hours during the month of Ramadan.
The Knowledge and Human Development Authority, Dubai's private education regulator, said private schools would have to cut their school day to five hours from the usual seven.
Private schools in Abu Dhabi would also have their school hours reduced to five.
Abu Dhabi private schools cannot start the day before 9:30am and must end by 3:30pm.
Private schools in the emirate have received Ramadan timing guidelines from the Abu Dhabi Department of Education and Knowledge (Adek).
"Each school is expected to cover the full content of the core subjects during those hours, and to consult with parents while selecting the appropriate schedule," Adek said.
Mohammed Darwish, chief executive officer of permits and compliance at KHDA, said schools could choose what times they start and end after consulting with their parent communities.
“During Ramadan, the whole school community – including pupils, teachers and parents – will be spending extra time in prayer with their families," Mr Darwish said.
"We ask schools to be mindful of this with regards to the amount of homework and assignments set for pupils.
"Every Ramadan, we practice the virtues of patience, togetherness, compassion and inner strength, and this year we will need to draw on these virtues more than ever.”