Mad Toy (original title: El juguete rabioso: "The rabid toy") is the debut novel by Argentinean author Roberto Arlt. Published in 1926 by Editorial Latina, it is markedly autobiographical in nature. The original manuscripts were written in the 1920s and were drafted by Arlt in the mountains of Córdoba, in a time when his wife, Carmen, who suffered complications from tuberculosis, needed to move to the mountains to recover from her illness. Arlt invested a considerable amount of money in businesses that did not grow, and had to accompany his wife, so he began work on Mad Toy.

Upon his return to Buenos Aires, Arlt tried to publish his novel in the Los Nuevos collection of the publisher Claridad, but the editor of the collection, Elías Castelnuovo, did not like the book. It was then when chance brought him to Ricardo Güiraldes, who, after hearing readings of the book, encouraged Arlt to continue looking for a publisher, and gave him a job as a secretary.