Dozens of secondary schools are closed across Tipperary and the rest of the country today as ASTI members are out on the picket lines.
The row centres on issues over pay for newly qualified teachers.
Today is the first of 7 planned days of action
Over 500 schools are shut across the country as ASTI members take the industrial action in the row over pay.
The action is centred on the pay scale for newly qualified teachers, currently staff hired after 2011 are paid less than those who qualified before the crash.
Speaking to Tipp FM, teachers in Cahir, Clonmel and Nenagh say even if the pay issue doesn't affect them personally, they have to stick together
Pay isn't the only issue teachers are unhappy with.
Problems with supervision and substitution duties may mean schools don't re-open after next week's mid-term break.
The Education Minister says he's disappointed that schools are closed due to strike action and he's hit out at the ASTI for withdrawal of substitution and supervision duties from the 7th November.
Richard Bruton Bruton says that issue can be readily resolved
Today's action by the ASTI has also forced the closure of 43 dual-union Education Training Board schools.
The remaining 235 schools which are staffed by members of the TUI are operating as normal.
But, speaking to Tipp FM News, several teachers say they're determined to keep going until an agreement can be reached.