Schools will shut down around the country for a day next month after teachers voted to strike over planned changes to examinations.
The secondary school walkout, by the Association of Secondary Teachers of Ireland (Asti) and the Teachers' Union of Ireland (TUI), has been set for Tuesday December 2.
The trade unions said they will stage another day of industrial action in January, in a date yet to be decided, over their row with education chiefs about changes to the junior certificate exams.
Both unions represent 27,000 second level teachers.
In a joint statement, they said they welcomed recent progress in negotiations with the Department of Education and Skills but insisted critically important issues remain unresolved.
"Teachers favour positive, appropriately planned and fully resourced improvement and consistently campaign for this," the statement said.
"They have reiterated their support for improvements to the junior cycle, but serious objections and concerns about aspects of the new programme remain.
"Notwithstanding the progress made in the recent negotiations, this is unacceptable."
But Education Minister Jan O'Sullivan said the strike action was "disappointing and disproportionate".
"It is deeply regrettable that the Asti and the TUI have decided to embark on a course of action that will disrupt schools and cause serious inconvenience for students and their families," she said.
"This decision is at variance with the potential for progress on junior cycle reform that is currently on the table."
Ms O'Sullivan said she has accepted genuine concerns expressed by teachers over proposed changes to the junior certificate over recent months and had offered a new compromise earlier this week.
"This new offer has the capacity to break the impasse and enable us to move forward and introduce a reformed junior cycle that is in the interests of students," she said.
"Unfortunately, both unions have decided not to engage and will now embark on unnecessary and disproportionate strike action."
Ms O'Sullivan has urged both unions to get back around the table for talks.