Soledad Juliana Villafranca Los Arcos (1880–1948) was a Spanish anarchist known for teaching at the Escuela Moderna and as a companion of Francisco Ferrer.

[4] In Barcelona, Villafranca and her sisters met Francisco Ferrer, who had founded the secular, rationalist Escuela Moderna school.

[3] He had sent her a letter prior to the bombing attentat that raised suspicion of Villafranca as a potential co-conspirator alongside Ferrer.

[5] Freed from implication in the event, Villafranca accompanied Ferrer during his 1907–1909 exile, where they spread anarchist propaganda across Europe.

[2][3] They visited multiple European cities including Antwerp and Paris, telling the story of their persecution and meeting the defense organizations created in their name.