The Alt Llobregat insurrection was a revolutionary general strike which took place in central Catalonia, in the northeast of Spain, in January 1932. Initially organised as a wildcat strike by miners in Fígols, who were protesting against low wages and poor working conditions, it soon turned into a general revolt and spread throughout the region. Workers seized local institutions, disarmed the police and proclaimed libertarian communism, all without any killing taking place. Within a week, the rebellion was suppressed by the Spanish Army. A subsequent rebellion in Aragon was also suppressed. In the wake of the insurrection, many anarchist activists were imprisoned or deported. The suppression of the insurrection caused a split in the Confederación Nacional del Trabajo, with its radical faction ultimately taking control of the organisation and the moderate faction splitting off to form the Syndicalist Party. Further insurrections were carried out by CNT activists in January and December 1933.

When the Second Spanish Republic was proclaimed on 14 April 1931, it brought an end to years of dictatorship which had driven the Spanish anarchist movement underground and forced its members into exile. The drafting of the Spanish Constitution of 1931 caused divisions in the Provisional Government. The separation of church and state was approved by the Constituent Cortes on 13 October 1931, with 178 votes in favour and 59 opposed. Members of the Liberal Republican Right, including Prime Minister Niceto Alcalá-Zamora and Interior Minister Miguel Maura, resigned from the provisional government over the issue.

The Spanish Socialist Workers' Party (PSOE), Radical Socialist Republican Party (PRRS) and Republican Action (AR) then came together to form a new left-wing government, excluding the right-wing republican parties. Manuel Azaña became the new prime minister, Santiago Casares Quiroga took over as Interior Minister and José Giral was appointed as Navy Minister. Without the influence of business owners and the Catholic clergy over the new government, many in the working class hoped they would address unemployment and land reform, but neither of these came to fruition. Instead, on 20 October, the government passed the Law for the Defense of the Republic, which increased the power of the Interior Ministry. On 9 December 1931, the Constituent Cortes approved the new constitution and elected Alcalá-Zamora as the first President of the Republic. On 11 December, Alcalá-Zamora accepted the nomination, swore to uphold the new constitution and proclaimed the day a national holiday.

While the government ratified the constitution, social conflict spread throughout the nascent Spanish Republic. In Zaragoza, workers proclaimed a general strike; in Xixón, the occupation of factories took place, culminating with the violent intervention of the Civil Guard, which killed 1 worker and wounded 11 others. On 31 December, Casares Quiroga dispatched the Civil Guard to the Extremaduran town of Castilblanco to suppress a strike action by the local peasantry. Local activists responded to the intervention by surrounding the Civil Guards and killing them. The Civil Guard retaliated against villages throughout the country, attacking La Almarcha, Calzada de Calatrava and Puertollano in New Castile. In the Aragonese town of Épila, the Civil Guard opened fire on striking workers, killing 2 people and wounding several others. The Civil Guard also attacked striking workers in the Valencian town of Xeresa, killing 4 people and wounding 3 others. In the Riojan town of Arnedo, the Civil Guard again opened fire on striking workers, killing 6 men and 5 women and wounding 18 men and 11 women.

In the anarchist newspaper Tierra y Libertad, the Iberian Anarchist Federation (FAI) proclaimed that the country had been "kidnapped" by the Civil Guard and printed graphic depictions of the violence. In the Valencian city of Villena, the novelist Pío Baroja proclaimed that the Republic had killed more people in a few months than the monarchy had in forty years. The events in Épila, Xeresa and Arnedo provoked a furious response from anarcho-syndicalists in Barcelona, who began to speak of carrying out a revolution against the Republic.

Despite the changes brought by the new Republican constitution, which had officially declared Spain to be a workers' republic, low wages and poor working conditions prevailed for miners and textile workers in central Catalonia. Since June 1931, deteriorating working conditions for potash miners in the Llobregat and Cardener river valleys had caused a rise in social tensions. José Enrique de Olano [es], the autocratic Count of Fígols [es], owned the coal and potash mines in Alt Llobregat. He forced the miners to work in unsafe conditions, paid them in scrip and restricted their life to a company town, where food was purchased from the company store. He also refused his workers the rights to freedom of assembly and freedom of association, and effectively controlled the Civil Guard in the region. The mining company made use of the Civil Guard to arrest disobedient workers, attack their unions and shut down left-wing publications. Many of the miners who had migrated from Cartagena considered returning to their home region, while others began to consider violence. Meanwhile, in the regional capital of Manresa, Joan Selves [ca] reported that employers had refused to comply with the new minimum wage law and continued to pay textile workers starvation wages.

Members of the Confederación Nacional del Trabajo (CNT), an anarcho-syndicalist union, put together a plan to channel the workers' discontent into an insurrection. In early January 1932, the anarchist activists Buenaventura Durruti, Vicente Pérez and Arturo Parera embarked on a speaking tour of the region. They encouraged workers to rise up in revolution against capitalism and the state, and showed them how to manufacture improvised explosive devices from dynamite and tin cans. In Tierra y Libertad, Felipe Alaiz warned that a dictatorship was being established in Spain by the Socialist and Republican parties, and called for anarchists to take direct action against the government. Historians Gerald Brenan, Pierre Broué, Émile Temime [fr] and Hugh Thomas would later attribute the instigation of the insurrection to the Iberian Anarchist Federation (FAI), but Parera himself claimed that the FAI had not participated in an organisational capacity.

On 18 January 1932, miners of the Sant Corneli Colony [ca] in Fígols carried out a wildcat strike, demanding improvements to their living and working conditions. As they believed the strike would only succeed if they could prevent their employers from repressing it, they disarmed the Civil Guard and the Sometent parapolice force, and they coordinated workers' patrols of the town's streets. The flag of the CNT was raised above the town hall and from the steeple of the local church. Before long, the workers of Fígols had formed a revolutionary committee, which proclaimed the establishment of libertarian communism in the region. According to an oral history by historian Cristina Borderias, the proclamation of communism was broadly accepted by the insurgent populace, for whom it meant social justice and freedom.