The health body had previously said there was no evidence face masks worked but now agrees they are better than nothing.
The World Health Organisation (WHO) is now recommending the use of face masks where social distancing is not possible.
WHO director-general Tedros Adhanom Ghebreyesus announced the change in recommendation on Friday, saying the organisation is now recommending people wear masks in areas where there is widespread COVID-19 transmission.
He said people should wear them in places such as public transport or shops, where social distancing is not possible
People over the age of 60 or those with underlying medical conditions should specifically wear a medical mask where social distancing cannot be maintained, he added.
Countries around the world have adopted the use of face masks, despite WHO previously saying they were not effective.
Britons using public transport must wear face coverings from 15 June after Boris Johnson changed his mind about their effectiveness.
Previously, the WHO only recommended healthcare workers, those with COVID-19 and their care givers wear masks.