This article examines the origins of Basque nationalism, major reasons why the terrorist organization ETA was founded, and the evolution of ETA's activities. Alongside this discussion, a parallel history of moderate nationalism pursued by the Basque Nationalist Party is also examined. The article recognizes an historical approach, since Basque nationalism has evolved in a specific way, and the historical, political and systemic changes that influenced the Basque Country in a different way than in other regions of Spain. In the literature, researchers show that Basque citizens are characterized by a strong sense of national identity. This is due firstly to the fact that many Basques identify themselves with the Basque Country rather than with Spain, which indicates a clear declaration of their national identity. This means that the Basques consider themselves a separate nation. The consequence of this is their desire to have a greater autonomy, preferably under the Spanish federal state, or to gain independence.