Don Segundo Sombra is a 1926 novel by Argentine rancher Ricardo Güiraldes.

Like José Hernández's poem of the 1870s, Martín Fierro, its protagonist is a gaucho.

Unlike the purely fictional character of Martin Fierro, the figure of Don Segundo Sombra was loosely based on and inspired by the real life of Segundo Ramírez, a native of the town of San Antonio de Areco in Buenos Aires Province.

Ricardo Güiraldes, who was a friend and literary partner of Jorge Luis Borges –they both founded the legendary magazine Proa –, managed to develop a simple and modern language for the novel: a mixture of literacy and colourful local expressions that earned him a major standing among the best representatives of "criollismo".

Even though it may be considered as having a continuity of sorts with '"Martin Fierro"', the protagonist is more than an extinguished gaucho elegy (like José Hernández's character is); instead, Güiraldes designed Don Segundo Sombra to present (or propose) a series of new ethical examples to a youth that Güiraldes considered disoriented and restless during his time.