Kilcoo (from Irish Cill Chua, meaning 'church of mourning' – from the legend that Saint Patrick's body stayed there while on its way to Downpatrick to be buried) is a small village and civil parish in County Down, Northern Ireland. It lies between Rathfriland and Castlewellan and is within the Newry, Mourne and Down District Council area. The village is on the A25 Dublin Road 6 kilometres (4 mi) south-west of Castlewellan. Kilcoo had a population 1415 people in the 2001 Census.

Near Kilcoo is Lough Island Reavy, a small man-made lough. East of the lough is Drumena Cashel, a stone ringfort that was used in the Early Christian period (500–1200 AD).

Saint Malachy's Primary School is a mixed gender school for students between the age of 4 and 11. It was opened in September 1970.

The village has one sporting club, Kilcoo GAC. This a Gaelic Athletic Association club with teams in Gaelic football and Camogie

Kilcoo is classified as a rural settlement by the Northern Ireland Statistics and Research Agency (NISRA) . Kilcoo is named as Tollymore Ward SOA 1 (Super Output Area) as the data contains the village itself and surrounding townlands of the village. On Census day (29 April 2001) there were 1415 people living in the Kilcoo area. Of these:

The civil parish is mainly in the historic barony of Iveagh Upper, Lower Half with one townland in Iveagh Upper, Upper Half.

The civil parish contains the following townlands: