An estimated 10,000 students from colleges and universities all over Ireland have gathered outside Leinster House to protest at the threatened reintroduction of tuition fees.
The garda dog unit and gardaí on horseback patrolled the area.
Almost 80 gardaí guarded the main gates of Leinster House on Kildare Street.
The Union of Students of Ireland told demonstrators it would continue to fight the reintroduction of third level fees.
USI's David Curran said students all over Ireland would organise and ensure that the campaign remained active.