Unions representing around twenty thousand teachers across Northern Ireland are due to go on strike on Tuesday in a dispute over pay.
It's the first time in five years that they have taken industrial action and the first time ever for the Ulster Teachers' Union.
Both primary and secondary schools are expected to close until midday.
The half-day strike action is being carried out by the three main teaching unions here - the UTU, the INTO and the NASUWT.
The NEU have also more recently joined their ranks after their members were balloted for strike action.
They insist it's a last resort as David Thompson, the principal of Dungannon Primary explained: "The action teachers have been forced to take has, at its heart, the children. Our education system has never been in a poorer state.
''Enough is enough. The industrial action is to highlight not only the profession's pay plight but equally the abject failure to resource the sector."
Lisburn principal Gillian Dunlop, head of Largymore Primary, said it is becoming impossible to retain young teachers.
"The pay and the difficulty in retaining staff because of the sheer workload is at the heart of why we feel we finally have no option other than to strike because the people who will suffer most unless this is addressed are the children,'' she said.
"Our pupils are at the very heart of why we are doing this because we want to attract the very best graduates to the profession who deserve to have the level of their professionalism rewarded."
A spokesperson for the Education Authority and other partners from management said there had been active engagement ''for many months on a teachers' pay settlement''.
However, they said: ''Negotiations are currently framed within the growing and unprecedented financial pressures facing the education sector.
"Guidance was issued to schools to help Principals assess and prepare for any potential disruption as the result of half day strike action on Tuesday.
"Principals are carrying out risk assessments and making arrangements for Tuesday, which will be communicated directly with parents via their own channels. Parents with any questions or concerns are advised to contact their child's school directly."
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