Ramadan is due to begin this week and is observed by millions of Muslims through a month of fasting.
Most people who are fasting will usually attend work - but are you entitled to request flexible working hours?
What about other rights you could be entitled to?
We spoke to employment rights experts to find out what you need to know.
The exact dates of Ramadan change every year as the Islamic calendar is based on lunar cycles.
You can read more about when Ramadan starts and finishes here.
Jim Moore, employee relations expert at HR consultants Hamilton Nash, said employers should be flexible during Ramadan due to the "physically and mentally challenging" aspects of fasting.
He told The Mirror: “This could involve letting employees adjust their hours, allowing for more flexibility around breaks during the day, or allowing some work from home.
“These don't have to be permanent arrangements, but will send an important signal to staff from different ethnic and religious backgrounds.“
Legally, workers are entitled to one 20-minute break every six hours under the Working Time Regulations 1998.
However, employers could suggest allowing break times to be split into smaller ones to allow workers observing Ramadan time to pray.
Mr Moore said employees should aim to give as much notice as possible to their boss, in writing, of their request to work flexibly - and the decision must be decided within three months.
He added: “An employee has the right to request flexible working arrangements if they have 26 weeks' service, although the Government is proposing to make it a right from day one.
“The employer has three months to respond to the request, and while they are not obliged to agree to the request, they will need to justify a refusal.“
Rhys Wyborn, employment expert at law firm, Shakespeare Martineau, also pointed out that religion is one of the protected characteristics under the Equality Act 2010.
He said this means employees must not be treated less favourably because they are fasting.
He added: “It is important that working hours are kept under review for employees observing Ramadan.
"While there is no legal right to a variation in hours due to religious belief, employers should be flexible and open to discussion with their staff, accommodating employee requests where possible.
“Employers should also be aware of arranging meetings where food might be present and give thought to ensuring there are onsite facilities where Muslim employees can pray without disruption if required."
