The 1977 Atocha massacre was an attack by right-wing extremists in the center of Madrid on 24 January 1977, which saw the assassination of five labor activists from the Communist Party of Spain (PCE) and the workers' federation Comisiones Obreras (CC.OO).

Intended to provoke a violent left-wing response that would provide legitimacy for a subsequent right-wing counter coup d'état, the massacre had an immediate opposite effect, generating mass popular revulsion of the far-right and accelerating the legalization of the long-banned Communist Party.

On the evening of 24 January, three men entered a legal support office for workers run by the PCE on Atocha Street in central Madrid, and opened fire on all present.

Severely wounded in the attack were Miguel Sarabia Gil, Alejandro Ruiz-Huerta Carbonell, Luis Ramos Pardo and Dolores González Ruiz.

Writing on the 40th anniversary of the massacre, journalist Juancho Dumall noted: "It was a terrorist act that marked the future of the country in a way that the murderers would never have suspected and, instead, was the one desired by the victims."

Their target was Joaquín Navarro, the general secretary of Comisiones Obreras, who was then leading a transport strike in Madrid, had fought corruption within the sector, and had denounced the state-controlled labor organization Sindicato Vertical.

The remaining four, Dolores González Ruiz (the wife of Sauquillo), Miguel Sarabia, Alejandro Ruiz-Huerta and Luis Ramos Pardo were gravely injured, but survived.

[9] Ultra right-wing elements of the armed forces and high-ranking officials from the Franco regime, known as the Búnker,[10] were to varying degrees engaged in a strategy of tension[11] designed to reverse Spain's transition to constitutional democracy.

[12][13] The open emergence of independent labor unions in 1976, although still illegal, and an explosion in demands for improvements in working conditions and political reform, led to an upsurge in industrial strife across the country.

[15] On 23 January, a student, Arturo Ruiz, was murdered by members of the far-right Apostolic Anticommunist Alliance (also known as Triple A) during a demonstration calling for an amnesty for political prisoners.

On 24 January, at a protest called to highlight Ruiz's death the day before, police fired tear gas canisters, one of which hit and killed a university student, Mariluz Nájera.

[19][20] The PCE was legalized soon after on 9 April 1977;[21] the Party's earlier embrace of Eurocommunism (essentially a rejection of Soviet-style socialism) and a highly visible role in promoting a peaceful response to the massacre allowed the government the necessary political space to lift the ban in place since 1939.

[24] Lawyer José María Mohedano recalled: "They had the power of a Franco-era labor union that was still alive and working, as well as the support of some police officers and the entire far-right.

"[25] They were all linked, directly and indirectly, to the far-right extremist parties the Fuerza Nueva (New Force) and Guerrilleros de Cristo Rey (Warriors of Christ the King).

[29] After more than 20 years on the run, García Juliá was rearrested in Brazil in 2018, extradited to Spain in February 2020, and transferred to Soto del Real prison to serve the remainder of his sentence.

[30] One of the survivors, Miguel Ángel Sarabia, commented in 2005: "Although now it may seem a small thing, the 1980 trial of the Atocha murderers – despite the arrogance of the accused ... – it was the first time that the extreme right was sitting on the bench, tried and condemned.

[32] This theory was further supported in October 1990 after revelations from the Italian CESIS (Executive Committee for Intelligence and Security Services) concerning Operation Gladio, a clandestine anti-communist structure created during the Cold War.

[39] Journalist Juancho Dumall, writing in 2017 on the 40th anniversary of the massacre, highlighted that the attack had the opposite effect of what was intended: "It was a terrorist act that marked the future of the country in a way that the murderers would never have suspected and, instead, was the one desired by the victims.