Ovidio Cátulo González Castillo (6 August 1906 – 19 October 1975) was an Argentine poet and tango music composer. He was the author of many famous works, such as Organito de la tarde, El aguacero (lyrics by José González Castillo), Tinta roja and Caserón de tejas (both with music by Sebastián Piana), María and La última curda (both with music by Aníbal Troilo), and El último café (with music by Héctor Stamponi). The tango La calesita, which he composed with Mariano Mores, inspired the film of the same name directed in 1962 by Hugo del Carril.

His father, José González Castillo, an anarchist, wanted to list himself in the civil registry as Descanso Dominical González Castillo, but was convinced by his friends not to, and kept his other name. As an infant, Cátulo lived in Chile, where his father was exiled because of his anarchist ideology. He returned to Argentina in 1913. Cátulo later affiliated with the Communist Party.