Mariners' Church, Dún Laoghaire, Maritime church in Dún Laoghaire, Ireland.

Mariners' Church is a former Church of Ireland church on Haigh Terrace in Dún Laoghaire, built to serve seafarers. Its original 1843 design by Joseph Welland consisted of a nave and transepts; a spire by Raffles Browne and lancet windows were added between 1862 and 1867, and a chancel followed in 1884. It now houses the National Maritime Museum of Ireland.

Built by subscription from 1836 as the Protestant Episcopal Mariners' Church at Kingstown Harbour, it was designed by Joseph Welland and consecrated on 25 June 1843. A spire by Raffles Browne followed in 1865 and a chancel in 1884. Worship ended at Easter 1972; the Maritime Institute of Ireland signed a lease in 1974, and President Patrick Hillery opened the National Maritime Museum of Ireland in 1978.

The church was built for the spiritual needs of officers and sailors at Kingstown Harbour, and its first chaplain was Richard Sinclair Brooke. The Maritime Institute of Ireland leased the building in 1974, and it became the National Maritime Museum in 1978. The former church now displays maritime exhibits, and the building itself retains its ecclesiastical layout.

The museum occupies the former church on Haigh Terrace, a short walk from Dún Laoghaire's centre and the DART station. The entrance is at the west end, beneath the spire added in 1865. Inside, the nave and transepts form a single open hall; the chancel, added in 1884, holds further displays. The building was renovated in 2011, with improvements to the roof, interior and electrical systems.

The first chaplain, Richard Brooke, called the new church "large and gaunt and lofty and ugly a satire on taste, a libel of all ecclesiastical rule, mocking at proportion and symmetry". The building was consecrated in 1843 with only a nave and transepts; the spire by Raffles Browne followed in 1865 and the chancel in 1884.