PAStrike action is set to close schools in Perth and Kinross for two weeks after the largest council union rejected a national pay deal.
The walkout by Unison members is due to begin on 21 October and will affect 50 schools and early years centres.
It will start immediately after the two-week October school holiday, meaning schools could be shut for a full month.
Thousands of Unison members (86%), including waste and recycling workers as well as education staff, turned down the national offer.
That offer was for a £1,292 per year or 3.6% rise – whichever was higher.
It was accepted by the two other big council unions, Unite and the GMB.
Councils across Scotland have agreed to implement the offer, meaning staff should get their rise and back pay soon.
The Scottish government and council leaders have said there is no more money for pay this year.
Meanwhile, Unison has also warned it will ballot all its council members across Scotland to see if they will go on strike.
The Unison action is targeting the constituency of First Minister John Swinney.
The union’s Perth and Kinross branch secretary Stuart Hope said taking strike action “is the last thing school and early years staff want to do”.
But he added: “Employees are taking this first stand on behalf of all local government workers because they’ve seen a decade of pay cuts and they see other sectors being offered deals of greater value.
“The Scottish government needs to understand that council staff need more than platitudes. Ministers must tackle the severe decline in local government funding and start to value councils and their dedicated workforce as they do other areas of public services.”
The local government body Cosla previously said it was “deeply disappointed” to learn that Unison had rejected its “strong” offer, which was above inflation.
Finance Secretary Shona Robison also said that industrial action “will serve no-one” and urged all parties to work together constructively.