Onésimo Redondo Ortega (Quintanilla de Abajo, Valladolid, 1905, February 16 – Labajos, Segovia, 1936, July 24) was a Spanish Falangist Fascist politician, founder of the Castilian Groups of Hispanic Action (Juntas Castellanas de Actuación Hispánica), a political group that merged with Ramiro Ledesma's Juntas de Ofensiva Nacional-Sindicalista (Unions of the National-Syndicalist Offensive) and José Antonio Primo de Rivera's Falange Española.
Onésimo Redondo was born in Quintanilla de Abajo, Valladolid (today renamed after Redondo as Quintanilla de Onésimo). He studied Law at the University of Salamanca and was Spanish teacher at the University of Mannheim (1927-1928), where he became acquainted with Nazism. (Historian Paul Preston has written that Redondo's anti-Semitism derived more from fifteenth century Castile than from Nazi models however, though he did translate Hitler's Mein Kampf into Spanish.) He began to work in Valladolid for the Castilian union of sugar beet harvesters and joined the Acción Nacional during his youth. He was greatly influenced by Enrique Herrera Oria, brother of the founder of the Asociacion Nacional Catolica de Propagandistas and editor of El Debate, Angel Herrera. Enrique Herrera believed that Communism, Freemasonry and Judaism were working to destroy religion and the Fatherland, and encouraged Onesimo to read the virulent anti-Jewish tract by w:fr:Léon de Poncins, Las fuerzas secretas de la Revolucion.
When the Second Republic was proclaimed (1931), and after the elections of June 1931 gave a majority to the Republican-Socialist coalition, he rejected democracy and broke from Acción Nacional. On June 13 in Valladolid he brought out the anti-Republican newspaper Libertad, where he wrote violently against Marxism, Jews (he published an annotated translation of The Protocols of the Elders of Zion), and bourgeois Capitalism, and admired European fascisms. He founded a fascist party, Juntas Castellanas de Actuación Hispánica (the Castilian Hispanic Action Groups) in August 1931 and in November it merged with Ramiro Ledesma Ramos's La Conquista del Estado to form the Juntas de Ofensiva Nacional Sindicalista (JONS). They refused to participate in elections as they believed in direct action. It was anti-democratic and imperialist and sought the "extermination of the Marxist parties". Redondo and the JHAC sought violent confrontation and recruits armed themselves for street fights with the predominantly Socialist working class of Valadolid, a city previously noted for the tranquility of its labour relations.
In Redondo's rhetoric, Moors, Jews, and the Left were all merged into one: by asserting that Marxism was a Jewish invention and implied the 're-africanisation' of Spain, Redondo was identifying Spain's archetypal others, the Jew and the Moor with the Right's new enemy: the Left. The war Spain needed to fight was a new 'reconquista', and ideologues such as Redondo offered a 'murderous justification of violence against the left.' 
In 1932, he collaborated with the frustrated coup d'état of General Sanjurjo and had to flee to Portugal. He returned to Valladolid in April 1933. On March 24, 1934 JONS and Falange Española merged. He was arrested on March 19, 1936 and he was moved to the prison of Ávila on June. He was liberated by the Nationalist after the beginning of the Civil War. He organized the Falange's militias in Valladolid and went to the Guadarrama mountains, where he died in combat on July 24. Francoist propaganda extolled him insistently as a war hero.
His widow, Mercedes Sanz Bachiller, founded Auxilio de Invierno (Winter Aid), after Auxilio Social (Social Aid), that was the welfare agency of Falange, further fully integrated in the Francoist State organization.
- Protocolos de los Sabios de Sión, Valladolid: Libertad, 1932
- Onésimo Redondo, caudillo de Castilla, Valladolid: Libertad, 1937 (newspaper articles and political speeches)
- El Estado Nacional, Valladolid: Libertad, 1938
- Obras Completas: edición cronológica (2 vols.), Madrid: Publicaciones Españolas, 1954-1955
- Textos políticos. Madrid: Doncel, 1975.
- Payne, Stanley: Falange: a history of Spanish fascism, Stanford: Stanford University Press, 1961
- Penella, Manuel: La Falange teórica, Barcelona: Planeta, 2006
- Rodríguez Jiménez, José Luis: Historia de la Falange Española de las JONS, Madrid: Alianza, 2000
- Ferrán Gallego, (2005). Ramiro Ledesma Ramos y el fascismo español. Madrid: Editorial Síntesis. ISBN 9788497563130
- Unearthing Franco's Legacy, p.56 , University of Notre Dame Press, 2010
- Unearthing Franco's Legacy, p.57
- Unearthing Franco's Legacy, pp.32-33
- (Spanish) Tribute web to Onésimo Redondo. Falangist and biased web, but with copious information about him.