A union says a “rolling programme” of further school strikes will go ahead in Scotland after members rejected a pay offer.
Unison said support staff – including janitors, canteen workers, classroom assistants and cleaners – had overwhelmingly voted against the deal.
Schools were disrupted for three days last month after the union turned down the offer from council body Cosla.
Cosla described the ballot result as “very disappointing”.
Both the Unite and GMB unions had suspended strike plans last month to consult with members.
But Unison pressed ahead with more than 21,000 of its members walking out in 1,868 schools.
Thousands of pupils were told to stay at home.
Unison said 89.92% of members had voted against the pay offer in a consultative ballot.
It said strike dates would be announced in the coming days.
Lilian Macer, the union’s Scottish secretary, said: “No one takes industrial action lightly. It’s a very difficult decision for anyone, but as much as this is about pay, it’s also about standing up for local services.
“The school staff taking part support children in school every day of the year, and many are parents with school-age children too.”
She added the sector had suffered from years of under-investment and members wanted children to be educated in “well-resourced, well-staffed schools”.
Ms Macer added: “No-one wants to cause disruption for pupils and parents, but school staff have been left with no other option.
“The blame must be laid squarely at the door of Cosla and Scottish ministers.”
Cosla said the ballot result was disappointing “given the strength of the offer on the table”.
Councillor Katie Hagmann, Cosla resources spokesperson, said: “Scotland’s council leaders value their workforce.
“We have listened to our trade unions, met all their asks and worked with Scottish government to put an incredibly strong half a billion pound pay package on the table.
“Offering almost 10 per cent or a £2,006 pay increase for our lowest paid workers, which the unions specifically asked for, and £1,929 or at least 5.5% for everyone else is as far as local government can go without impacting service and jobs.”
‘I support the staff’
Mum Gael McMahon told BBC Scotland that she was supportive of the strikes despite the disruption to parents like herself.
She said it was important for support staff to be paid the “right wage”.
“As a parent and constantly having to take time off work to take care of the kids, it does take its toll quite significantly,” she said.
“Especially when you’ve got a wee one as young as mine.
“But I’m in full support of the staff and they need to get the right wage, they absolutely have to.
“Fortunately my bosses are great and I’m able to do home-working as well as taking care of the kids, so it’s not as bad for me as it would be for other parents.”
Early years practitioner Anne-Marie Glasgow said she would be taking part in any upcoming strike action.
“We all need a decent wage,” she said. “And we are looking after the most important people, the children.
“I do feel sorry for people – it impacts our family as well, my daughter has to get her children looked after while she’s working.
“I’m a granny as well, and I also do foster care with vulnerable families and it impacts them as well.
“But what else could we do? We all do valuable jobs and we should get recognition for that.”
Unison said 57% of members had voted in the ballot, which opened on 3 October. It had recommended that members reject the proposal.
The Scottish government had freed up £80m of ring-fenced funding to enable the deal.
But Unison said members had not been provided with the full details of what the offer meant for them.
It also said it remained below the rate of inflation and would trigger cuts elsewhere.
GMB Scotland previously said the offer was “not perfect but a clear improvement” and moved to suspend strikes, along with Unite.
At the time, First Minister Humza Yousaf described the offer as “very good” but said it was for Cosla to lead the negotiations.
It is no surprise Unison members rejected the pay offer so overwhelmingly. It was made before last month’s three day strike which received solid support from members.
Now more disruption to schools is likely unless an improved pay offer is made. Unison does not have a specific figure in mind for the pay offer it would like, but there are other areas which could lead to a solution.
One is over how the pay rise would be funded. The union fears that without more Scottish government money for councils, even the current pay offer would mean cuts, savings and potential job losses.
The other is over agreeing a pathway towards a significant increase to the wages of the lowest paid council staff. The union wants a clearer and more specific pathway which would lead to all council workers earning at least £15 per hour.