The Educational Institute of Scotland (EIS) trade union had already announced school staff are to take part in what will be the first national strike action over pay for almost 40 years in a protest on Thursday, November 24.
After a meeting on Thursday afternoon where the union said no new offer was made, it extended that action, with two more strike dates now announced for early next year.
General secretary Andrea Bradley said “unless a fair pay offer is made” before the Christmas break there will be further strikes on January 10 and 11.
Staff in primary schools, special schools working with both primary and secondary age youngsters and early years teachers will all take action on January 10, the union said.
Meanwhile, secondary school teachers and those in secondary only special schools could now strike the following day.
The EIS has already rejected the 5% pay rise offered as being “wholly inadequate”.
Deputy First Minister John Swinney made clear to unions that finding extra cash to fund public sector pay rises beyond what has been offered would mean more cuts to services.
Mr Swinney said: “If I want to put any more money into a public sector pay deal, beyond what’s already on the table, I have to cut public expenditure and public services.”
Ms Bradley stated: “All EIS members in all of Scotland’s schools will be called upon to take strike action next week unless a fair pay offer is made in time.
“Following this, the EIS has allowed for a period of further negotiation up until the Christmas break, giving yet another opportunity for an agreement to be reached.
“Should no acceptable offer be received from employers by this time, our members will be called to take further strike action on two days in early January.”
She said that the “ball is very much in the court of” the Scottish Government and the local authority body Cosla.
Ms Bradley insisted: “Only an improved and acceptable offer can prevent strike action and an escalation to further action in this dispute.”
The union leader said it was “extremely disappointing” that the meeting of the Scottish Negotiating Committee for Teachers (SNCT) – which brings together the union with council leaders and the Scottish Government – had not resulted in a new pay offer.
She claimed Thursday’s meeting “seems to have been called simply to make it appear as though talks are progressing”.
Ms Bradley said: “In fact, this meeting simply went round the houses in areas that have been covered many times before, with still no improvement to the 5% offer that Scotland’s teachers overwhelming rejected in a ballot some three months ago.
“Scotland’s’ teachers – and Scotland’s young people – deserve far better from Cosla and the Scottish Government.”