Kilternan (Irish: Cill Tiarnáin, meaning "Church of Tiarnán") is a village in County of Dún Laoghaire-Rathdown, in the foothills of the Wicklow Mountains south of Dublin, near the border with County Wicklow.
Separated from the continuous built-up Dublin area, it is a suburban village in rural surroundings at the crossroads of the R117 and R116 regional roads.
Proposed development scheduled to begin in 2009 would have expanded the urban area, but the plans were forestalled by the bursting of the property bubble in Ireland.
Kilternan's most notable buildings are the Church of Ireland Parish Church of Kilternan which dates from 1826, the timber-built Catholic Church of Our Lady of the Wayside (Blessed and Dedicated on 14 July 1929), or 'The Blue Church' as it is known locally after its Marian colour, and the Golden Ball, or Palmers, pub which has been closed since June 2012 These names are joined at the local soccer club, Wayside Celtic whose ground is known as The Golden Ball. Kilternan is also home to two rugby clubs, De La Salle Palmerston and Old Wesley RFC known locally as Salmo and Wezz whose grounds are located at Kirwan Park (DLSP) and on the Ballycorus road (Wesley). Kirwan Park is located at the northern end of the village, while the Ballycorus road is located at the southern end of the village.
Kilternan lacks a traditional village centre or 'Main Street'. It is the location of Ireland's only (artificial) ski slope.
Road signs are somewhat confused regarding the correct spelling of the name of the area. For example; signs on the M50 motorway (Junction 15) call it Kilternan while signs at the junction on the adjoining roads refer to "Kiltiernan", even though both sets were erected at roughly the same time. Local government documents and ordnance survey maps refer to Kiltiernan while many local people spell the name without the "i". Locally, Kilternan is the most acceptable form.