The Knowledge and Human Development Authority, the emirate's private education regulator, set out the decision-making powers for schools in a guide released on Wednesday.
Schools can start the day early or finish it later, provided they have first consulted with parents of pupils.
On Fridays, schools can finish no later than noon.
Public sector workers will adopt a four-and-a-half-day working week from January 1. Employees will complete full working days from Monday to Thursday, with a half-day on Friday. Saturday and Sunday will be the new weekend for government workers.
All public and private schools will implement the same timetable, with pupils attending lessons from Monday to Thursday, with a half-day on Friday,
Dubai's regulator has allowed for some flexibility so that schools are able to meet their curriculum requirements.
Education chiefs in Sharjah have also taken steps to support the transition to the new working week.
In Sharjah, the public sector will work from Monday to Thursday, with employees enjoying a three-day weekend.
Private schools in Sharjah will be allowed to increase daily learning hours or extend the academic year by a week to adapt to the schedule.
From Monday, January 3, all pupils across the Emirates are due to return to classrooms for the first time since the start of the Covid-19 outbreak.
Around the UAE, some Covid-19 restrictions will be lifted and a shorter week with longer days will await pupils as 2022 ushers in a new academic term.