Leaders say the safety measure – a requirement scrapped when restrictions were lifted – will help to curb rising infection rates in Wolverhampton.
It comes as councils across the region and nationally reported the number of Covid-19 cases were rocketing, with people asked to continue to take tests.
Councillor Dr Michael Hardacre, cabinet member for education and skills in Wolverhampton, said: "We need to do all we can to stop the spread of Covid-19, and the wearing of face coverings has an important role to play in this.
"Face coverings were mandatory in communal areas in secondary schools throughout the spring and summer term and certainly seemed to help keep infections down so, with cases now rising once more, it is sensible for schools to adopt this policy once more."
A number of secondary schools in the city have already re-introduced the requirement to wear face coverings unless an individual is exempt for medical reasons, as was the case after the reopening of schools earlier this year.
Headteacher Andrea Stephens, of Colton Hills Community School on Jeremy Road which has already adopted the measure, said: "We have taken a range of measures as the number of confirmed positive cases within school has risen, particularly in Year 8, and are working closely with Public Health to ensure we are doing all we can to prevent any further spread.
"With this in mind, we have already reviewed our current safety measures and have decided to re-introduce face coverings for staff and students in communal areas or when staff are in close contact with students in the classroom, unless they are exempt. In addition we have staggered departure times for Year 8 pupils and have asked all adults to wear face coverings when they are on the school run.
"These changes will remain in place until further notice, and we are hoping they will send a clear message to all in our community that the virus is still with us and that we have a duty to protect those who are most vulnerable.
"We hope it will instil confidence with staff, parents and our students that we are doing all that we can to keep everyone safe while maintaining high standards of education."
In addition to the new guidance around face coverings, which should also be worn on school transport, the council is reminding secondary school pupils, and all school staff, that they should take a rapid Covid-19 test twice a week to identify cases in people without symptoms.
Latest figures show there were 369.5 new cases of Covid-19 per 100,000 people in Wolverhampton over the last seven days. That means 972 people tested positive for the virus in that same period – though the true number of cases will likely be higher.