Masks will be required in all Pennsylvania K-12 schools, early learning programs and child care providers beginning Tuesday, Sept. 7.
The State Department of Health announced the order Tuesday amid rising COVID-19 cases, including in children.
"In Pennsylvania, just since school began reopening, more than 5,000 students have tested positive," said Acting Health Secretary Alison Beam.
The order applies to everyone indoors at K-12 public schools, cyber charter schools, private and parochial schools, early learning centers, childcare providers, career and technical centers and intermediate units. The order has eight exceptions, including school sports and outdoor activities.
Gov. Tom Wolf called the order "necessary" to keep kids in classrooms.
"Our schools and students have experienced a lot of disruption over the past year and a half, but we have the tools now to keep them as safe as possible while they go back to school," Wolf said.
Wolf wrote a letter to GOP leaders last week asking them to call state legislators back to Harrisburg to work on a bill mandating masks in schools. Republicans rejected Wolf's request in a response, saying it should remain up to districts and schools.
District officials have battled increasing debate and controversy over mask policies in recent weeks.
Groups of parents from North Allegheny and Canon-McMillan School Districts took their concerns to court, asking judges to order mandatory masking in their schools.
Asked why he didn't order masks sooner to avoid pushback against individual districts, Wolf said he had hoped districts would implement mandatory masking on their own.
"The effort was done, I don't know how many weeks ago, in terms of saying to the school boards, 'make this happen. These are the CDC guidelines. I want to have you do the right thing here,'" Wolf said. "That didn't happen. I said to the General Assembly, 'you take this and run with it and do the right thing here.' They didn't do it. So, it's left to me. Maybe if we had all run together earlier it would have been nicer, but that didn't happen. I'm moving as quickly as I can here."
Wolf said parents and schools will be expected to enforce the new order.
"The real penalty is going to be imposed by parents upset with their school district for not doing the right thing by their children," he said.
The state plans to reevaluate the policy at the beginning of October.
Wolf received support from health officials in Allegheny County. Health Director Dr. Debra Bogen released a statement Tuesday afternoon.
“Over the past few weeks and months, we have urged school districts to follow the CDC guidelines to require masking in schools. We have been fortunate that 26 of our districts have put full mandates in place and another six have some hybrid requirement.
“In the last month, we have seen increasing cases of COVID-19 among children, especially those who are not yet eligible for vaccination. Today’s action by the state ensures that we are all taking the appropriate steps to protect our children while also providing for reasonable exceptions. I wholeheartedly support them in this decision and thank them for taking this step.”