Up to 27,000 teachers will protest outside secondary schools across the country, over their concerns about planned changes to the Junior Cert.
Rallies are planned outside every secondary school at lunch time, by members of the Association of Secondary Teachers of Ireland and the Teachers Union of Ireland.
They are concerned that changes to the Junior Cert are being introduced next year without proper consultation or the necessary resources.
The President of the TUI, Gerard Craughwell, says schools won't be disrupted by the action.