Secondary school pupils in Scotland will have to wear face coverings in corridors, communal areas and on school buses from Monday, August 31.
John Swinney confirmed the move on BBC Radio Scotland this morning.
The guidance will apply to all pupils over the age of 12.
During the Scottish Government's daily coronavirus briefing yesterday, Nicola Sturgeon advised the Education Secretary was in talks with teachers ahead of the recommendations being implemented.
She said: "Over the weekend the World Health Organisation issues guidance on young people and mask wearing. They said that young people over the age of 12 in school, where social distancing is not possible, then face coverings should be recommended.
"I said last week that we were looking closely at this issue and taking advice from our expert group. So to update you today, I can confirm that the Education Secretary is in the final stages of consulting teachers and local authorities on face coverings.
"The recommendation is for the use of face coverings by staff and pupils in secondary schools, when they are moving around in corridors and communal areas.
"We are consulting on this specific measure because mixing between different groups is more likely in corridors and communal areas - increasing the potential for transmission of the virus. Crowding and close contact in these areas is more likely, and voices may be raised - resulting in greater potential for creating aerosols, and finally, there is often less scope for effective ventilation in these areas.
"This is a position that would reflect - and actually go slightly beyond - current WHO guidance. We are also considering the position on school transport and will set out our conclusion in next few days.
"We are not currently consulting on any proposals to wear face coverings in the classroom. That is because there is greater scope for physical distancing in the classroom, and face coverings are more likely to interfere with teaching.
"I would emphasise, however, that where there are outbreaks, it remains an option for Incident Management Teams to recommend more extensive use of face masks if they believe that is required to protect public health.
"And more generally, the reason why we are consulting at this stage on a limited use of face coverings – and indeed, the reason why we have been able to fully reopen schools - is because of the relatively low levels of transmission we currently see in the community.
"That highlights a fundamental point. The best way to ensure that schools can reopen safely – and that businesses can reopen and stay open – is for all of us to play our part in keeping transmission rates within the community as low as possible."
