Las Sergas de Esplandián is a novel written by Garci Rodríguez de Montalvo in the late fifteenth or early sixteenth century. The novel is a sequel to a popular fifteenth century set of chivalric romance novels, Amadís de Gaula. The novel achieved particular notability in 1862, when Edward Everett Hale concluded that the novel was the origin of the name California.

Garci Rodríguez de Montalvo was a Castilian author who arranged the modern version of the chivalric romance Amadís de Gaula, originally written in three books in the 14th century by an unknown author. Montalvo incorporated a fourth book in the original series, and followed it with a sequel, Las sergas de Esplandián. It is the sequel that Montalvo is most often noted for, mainly because within the book he coined the word California.