The General Assemblies of Alava are the equivalent of a House of Parliament for this Historic Territory. They are formed by 51 representatives called Procurators, or Members, elected every four years by universal suffrage.

The General Assemblies govern within the framework of their legislative powers. The duties of the Assemblies include the election from among their members of the President of the Council (the General Deputy), the approval of the provincial budgets and control over their administration.

The General Assemblies date back to late 1463, in Ribavellosa, when sixteen Procurators from different Brotherhoods and a jurist sent by King Enrique IV drew up 60 bye-laws, replacing those in force up until 1458.

These bye-laws put an end to the conflicts that had troubled the land since the end of the 14th century, causing disagreements between the peasants, townsfolk and local noblemen and the direct heirs of the Arriaga Brotherhood, who had taken possession of the territory on the strength of their loyalty to the House of Trastámara. This social and political movement towards integration gave practical definition to the boundaries of the province as it is known today.

The legal basis adopted by Alava in modern times were its long-standing laws and bye-laws. The very first written example is found in the Royal Privilege awarded by the Crown of Castile to this province in 1417, which consisted of 34 bye-laws which were subsequently added to and specified in more detail.

The Brotherhoods which sprang up in mediaeval times formed the basis for local government, and their roots lay in the will of free men to join forces in order to fight against the atrocities committed by the powerful or against outlaws and other criminals. Fifty-three Brotherhoods were grouped together in six "Cuadrillas". The Brotherhoods were represented before the Assemblies, as were the Municipalities.

Centuries ago, the General Assemblies, the Brotherhoods' highest governing body, were formed by the mayors or procurators of the Brotherhoods, the Provincial Treasurer, the General Deputy, two notary publics and a representative from each township.