Don Agustín Maria Muñoz y de Borbon, 1st Duke of Tarancón, Grandee of Spain (es: Don Agustín Maria Muñoz, Duque de Tarancón) (15 March 1837 – 15 July 1855) was the eldest son of Maria Christina, Queen mother and Regent of Spain, and of her morganatic second husband Agustín Fernando Muñoz, Duke of Riánsares (made duke in 1844 by his step-daughter, Isabella II of Spain).

Muñoz was born in Madrid while his mother was still Regent of Spain and his parents' marriage was not publicly known.

In 1842 his mother purchased the Château de Malmaison where Muñoz and his siblings grew up.

In 1844 Muñoz's half-sister Queen Isabella II of Spain was declared to be of age.

[1] With exile imposed on his mother by the Spanish Courts first, and by his own sister Queen Isabella II, Muñoz moved with her mother to France, where he would live in the town of Rueil-Malmaison, near Paris, settling in the Château de Malmaison who had previously belonged to the Empress Josephine.