Ali-Akbar Baghani was arrested by plainclothes security agents at 9.30 am on Monday as he was teaching in Tehran, state-run news agencies reported. The arrest came as a shock to pupils in the class who were in the middle of an examination.
The arrest took place without prior coordination with the school principal.
There has been a surge in anti-government teachers demonstrations in Iran over the past few weeks, mostly in protest to low salaries.
Some sources in Tehran have claimed that up to 1,000 teachers have been arrested in the course of the protests.
