The peculiar institutional structure of the Autonomous Community of the Basque Country has its origins in the individual rights and historical circumstances of its three provinces. Its institutional model is based on the co-existence of certain common institutions - the Basque Government and Parliament - with the Provincial Councils and the General Assemblies of each of the three provinces.

The 1979 Statute of Autonomy, together with the Basque Historic Territories Act, governs the relationship between these institutions based on the principle of political equality for the three territories (Alava, Bizkaia and Gipuzkoa) and respect for their own intrinsic individuality.