This document outlines the system of government in Ireland, North and South, by local, regional and national levels. It includes the functions of Dáil Éireann and the Northern Ireland Assembly, departmental roles and an outline of all-Island bodies created under the Belfast Agreement 1998. This resource aims to give a greater understanding of government structures in order to assist and encourage collaboration and cooperation in the area of ageing research within Ireland (North and South). Web links have been provided to guide the reader to original texts. Links to the original definition of titles and technical terms have also been added.