Scotland's largest teaching union is urging its members to reject a "final" pay offer, as a ballot gets under way.
Members of the Educational Institute of Scotland (EIS) will begin voting just days after thousands of teachers marched through Glasgow in support of a 10% pay rise.
The government and councils have offered 3% with some grades receiving bigger increases.
The union has described the offer as "smoke and mirrors" and "divisive".
The EIS claims teachers' pay has fallen by more than a fifth in real terms over the past decade - and says a bigger rise is needed to address problems with recruitment and retention of staff.
The Scottish government and Cosla have said the deal on offer is the best they can produce in the current financial climate.
'Not good enough'
The EIS will be urging members to turn down the offer in the ballot which runs for three weeks.
If they do this and further talks get nowhere, the union will hold a ballot on industrial action.
On Saturday, up to 30,000 teachers marched through Glasgow in support of the union's pay demand.
EIS general secretary Larry Flanagan said: "The EIS is clear that the current offer from the Scottish government and Cosla is not good enough, as it fails to address adequately the 24% real terms cut of the past decade; is divisive in nature; and will do little to attract the new teachers that Scotland desperately needs, or to retain the experienced teachers who offer so much to Scottish education.
"Our members turned out in record numbers on Saturday, and we are confident that they will also turn out in huge numbers in this ballot.
"An overwhelming vote to reject the current divisive offer should bring the Scottish government and Cosla back to the negotiating table - or else they risk forcing Scotland's teachers into a campaign of industrial action."
Education Secretary John Swinney said he "hugely valued" the work teachers do, and defended the offer.
He said: "Through a combination of a 3% increase for all staff earning up to £80,000, restructuring the main grade scale and annual progression, the majority of teachers receive a rise between 5% and 11%.
"I firmly believe this is a generous and fair offer which demonstrates the value both the Scottish government and local government place on the teaching profession."