The Irish National Teachers' Organisation (INTO) (Irish: Cumann Múinteoirí Éireann), founded in 1868, is the oldest and largest teachers' trade union in Ireland.

It represents teachers at primary level in the Republic of Ireland, and at primary and post-primary level in Northern Ireland.

The current INTO President (2023–24) is Dorothy McGinley;[3] John Boyle is the General Secretary and Mark McTaggart is the Northern Secretary.

[4] The union website claimed 50,042 members (43,141 in Republic of Ireland and 6,901 in Northern Ireland) as of February 2021.

[5] Next door to the union's head office on Parnell Square is Club na Múinteoirí (the Teachers' Club) which is operated by the INTO as a space for cultural and social events, including halls, meeting rooms, a bar, and a theatre in the basement.