The Army Reserve (AR) (Irish: Cúltaca an Airm) is the reserve land component of the Irish Defence Forces. It is the second line reserve of the Irish Army. The Army Reserve involves active military service on a part-time basis, and is one of two elements of the Reserve Defence Forces, the other element being the Naval Service Reserve (NSR).

It was established on 1 October 2005 to replace and reorganise the previous reserve organisation, and to improve training and courses along the lines of the regular, full-time Permanent Defence Forces (PDF). This reorganisation saw the creation of an overriding Reserve Defence Forces structure which spans both the Army and Naval Service Reserve.

Prior to the 2005 restructure, the land component of the reserve forces were known as the Fórsa Cosanta Áitiúil (FCA) (local defence force), which in turn has its origins in the units formed in 1920s. Army Reserve elements are now integrated with PDF units, under the "Single Force" framework.

In times of crisis or emergency, Reservists are liable to be called up on permanent service within the state or outside it by the Minister for Defence or Government of Ireland in accordance with the Defence Acts.