The ASTI members have voted to reject proposals offered by the Department of Education following strike action late last year.
In a ballot of the union’s 18,300 members, members voted by 52.5% to 47.5% to reject the proposals in the row over equal pay for young teachers as well as Junior Cert reform.
Commenting on the result of the ballot ASTI President Ed Byrne said: "Despite the implementation of punitive measures for ASTI members and threats of further measures, ASTI members are standing up for their most vulnerable colleagues and for their students."
He added: "Our members are standing firm and telling us to continue to hold the line on Junior Cycle reform and to vigorously pursue equal pay for equal work for our young teachers."
With the possibility of more strike action, the ASTI's Standing Committee say they'll meet next week to consider the result of the ballot:
"Standing Committee has already outlined the direction it will be taking on future actions and will meet next week to take the necessary decisions.
"Our students' education is a key reason why the proposals were rejected and we will, as always, have due cognisance of the impact of any industrial action on students and their families.
"However, we believe we have a duty to protect the education of the students sitting in our classrooms today and those students who will be sitting in our classrooms in five years and beyond."