Coláiste Íosagáin is a Catholic girls gaelcholáiste (Irish language secondary school) in Dublin, Ireland.

The school occupied temporary premises at Carysfort College, Blackrock from 1971–1975 when it moved to the Stillorgan Road new building.

[citation needed] Early in the 1990s it was deemed that the school's existing single storey buildings, built in the 1970s, were too small to accommodate the expansion of both Coláiste Eoin and Íosagáin.

It took many years of collecting voluntary donations from parents and other members of the public for the project to even reach the planning stage.

[citation needed] This restricted site condition caused the new building to be formed into two shared elements: a four storey academic block, and a sports hall with performance space.