The Teachers Union of Ireland (TUI) has rejected the Croke Park II agreement by a margin of more than four to one.
It is the first of the public service unions to deliver a ballot result and there is no surprise that the membership went with the union's 'No', recommendation.
The TUI executive will meet later this week to consider the outcome of the ballot and the union's next steps will also be debated at its annual congress next week.
As one of the smaller public service unions, the TUI result may not be key when the results of all public service union ballots are aggregated next month.
However, the TUI has already decided that it will not be bound by the majority decision of the Public Services Committee of the Irish Congress of Trades Unions (ICTU).
"The TUI position is that it is not for the Public Services Committee to determine working conditions for members of unions who have rejected the proposals", said TUI president Gerry Craughwell.
The TUI said the ballot turnout of over two-thirds of the union's membership was very high. Mr Craughwell said TUI members, both second-level teachers and college lecturers, "have spoken and they have said enough is enough".
"The feedback we received from members during the ballot is that while the pay proposals are a big issue for them, a further major issue is the savage and unwarranted attack on working conditions."
Fianna Fail education spokesperson Charlie McConalogue said the fact that TUI members felt they had no choice but to reject this agreement in such huge numbers was extremely worrying.
"The Government needs to start putting far more energy into listening to the concerns of public sector workers rather than just dismissing them outright," he said.