Ardscoil Éanna is a secondary school in Crumlin, Dublin, Ireland. It was established in 1939 by James J. O’Byrne, who had been interned in Frongoch in Wales for his role in the Easter Rising in 1916, and Margaret Pearse, sister of Pádraig Mac Piarais who had established Scoil Éanna in Ranelagh in 1908. It moved to its current site, Franshaw House, in the early 1940s. It is the oldest school in the Crumlin area and one of only fifteen schools in Ireland under lay Catholic control. The current principal, Étaín Ní Mhórdha, is a granddaughter of the founder, while the Board of Management is chaired by his daughter and the school owner, Eibhlín Ní Bhroin.
Until a fire in 2006, Ardscoil Éanna also had a primary school.
There have been four principals so far in Ardscoil Éanna's 70-year history: James J. O'Byrne; Réiltín Ní Bhroin; Mattie Moloney; and Étaín Ní Mhórdha.
Hollywood actor Gabriel Byrne, who returned as a teacher of Spanish and History in the school, attended Ardscoil Éanna as a student in the 1950s and 1960s. Byrne returned for the school's 70th anniversary celebrations where he was guest of honour among the 400 attendees.