NEU Cymru members from across Wales will be gathering outside the Senedd from 11am to protest about the supply agency rip-off in education.
Nicola Fitzpatrick, Interim Wales Secretary for the National Education Union (NEU) Cymru, said:
"Our members are holding this protest because they are fed up with the lack of progress on a national model for employing supply teachers. We need education supply members to be properly paid, with access to pensions, alongside the rest of the education workforce.
"Education is about learning, not about company profit. Enough is enough. It is time for Welsh Government to act."
A series of speeches are planned on the steps of the Senedd.