Pistolerismo refers both to a specific period of Spanish history, between the general strike of August 1917 and Primo de Rivera's coup in September 1923, and to the social phenomenon spread in many areas of Spain during which Spanish employers hired thugs to intimidate and often attack trade unionists and notable workers – and vice versa. It was characterized by the birth and proliferation of several armed groups composed of pistoleros ("gunfighters"), men specialized in the use of violence.

It reached its most tragic consequences in the region of Catalonia and especially in the city of Barcelona, where hundreds of people were killed or injured as consequence of political violence and social attacks. Above all, social clashes of these years played a fundamental role in the crisis of the Spanish Liberal State, whose existence definitely finished with de Rivera's coup.

At the beginning of 20th century, Spain was led by a parliamentary monarchy, also known as Spanish Restoration regime, born in 1874 after the end of the First Spanish Republic and the Restoration of the monarchy with Alfonso XII. The political system was organized around the so-called turno pacífico, the alternation of the two main parties, Liberal and Conservative, and the composition of governments was decided before political elections through a negotiation process between the Ministry of the Interior, the king and local chiefs.

The Spanish Liberal State was built on three main elements: the monarchy, the Catholic Church and the army. After the death of Alfonso XII in 1885, his posthumous child Alfonso XIII became king of Spain. He reigned until the birth of the Second Spanish Republic in 1931.

At that time the Church had a big influence on Spanish society. It organized the educational system and it was in charge of several hospitals and nursing homes. After the election of Pope Pope Leo XIII in 1878 there was a warming of relations between the Spanish State and the Church and in 1883 moderate members of the Catholic Party joined the Conservative Party. This event enabled clergymen to regain support within the Spanish bourgeoisie, which at the turn of the century gained more power and influence in social and political life. Nevertheless, the ecclesiastical world was also a perfect environment for anti-liberal ideas, culminating in the formation of an integralist catholic movement towards the end of the century.

The third bastion of the regime was the army, which from the middle of the 19th century became the referee of the political life. State authorities did not manage to submit it to their control and, as a consequence, soldiers affirmed their role as defenders of the social order. Moreover, political parties used to mobilize the army every time there were strikes, civil disorders and demonstrations. This attitude increased the number of social clashes and fostered the perception that violence was an available instrument for solving social and economic issues.

Pistolerismo had its roots in the crisis of the Restoration Regime, which from the end of the 19th century showed its weakness to face social and economic transformations in Spanish society. The fragility of the Spanish State, which was the consequence of internal and external factors, produced a growing social instability leading to the explosion of violence.

In the last decades of 19th century Spain experienced rapid but uneven industrialization which characterized only some areas of the country, especially the Catalonia region. A lot of workers moved from rural areas to big cities such as Barcelona, Valencia and Zaragoza in order to find a job in the factories.