International organizations are typically intergovernmental in nature and endowed with a bipolar institutional structure where organs of States are usually juxtaposed with the Secretariat. On these premises, in Non-Governmental Interests in Regional Organizations: The Role of Parliamentary, Socio-Economic and Territorial Institutions Elisa Tino aims at analysing the unexplored phenomenon of institutional multipolarism of regional organizations, namely the trend to establish institutions representing non-governmental interests. Particularly, illustrating their diffusion in various geographic areas, explaining rationales underlying their establishment and investigating their institutional aspects, Elisa Tino pinpoints the contribution of these institutions to the development of regional organizations both according to the functionalist approach and the constitutionalist one. Thus, she aims at providing food for thought in the study of international organizations.