Dunguaire Castle, Medieval castle in Kinvara, Ireland

Dunguaire Castle is a 16th-century tower house of grey limestone standing on a low rocky base beside the water. Its 23-metre tower has small dark windows and a stepped gable roof with a chimney and flagpole. A lower stone wall with a gabled roofline and a dark arched entrance adjoins it.

Dunguaire Castle is a 16th-century tower house built in 1520 by the Ó hEidhin (Hynes) clan, chiefs of the district around Kinvara. In the 17th century it passed to the Martyns of Galway; Richard Martyn, mayor of Galway in 1607–1608, lived here until 1642. His descendants held it until the end of the century, after which it fell into ruin. It was restored in 1924 by Oliver St. John Gogarty and again in the 1980s.

Oliver St. John Gogarty, the surgeon who served as James Joyce's model for Buck Mulligan in Ulysses, restored the castle in 1924 and held literary gatherings there, though he never lived in it. Nearby at Coole Park and Thoor Ballylee lived Lady Gregory and W.B. Yeats. From 1966 the castle opened to visitors and hosted medieval banquets.

The castle has been closed to visitors since 2023, after the Shannon Airport Group offered it for sale and Galway County Council declined to buy it. The gate on the paved path is therefore shut, and the tower and its defensive wall can only be seen from outside. The 23-metre tower stands beside the water near Kinvara, on the southeastern shore of Galway Bay.

The original dun of King Guaire, who died in 662, was probably the earthen bank with wall remains on the headland west of the castle, not the tower itself. The 16th-century tower house was raised in 1520 by Guaire's descendants, the Ó hEidhin (Hynes) clan.