Francisco de Orellana (c1500-c1549) was a Spanish explorer and conquistador.

Orellana took part in the Spanish conquest of Peru with Francisco Pizarro, and was one of Gonzalo Pizarro's lieutenants during Pizarro's 1538 expedition into the South American interior.

At what is today the Napo River, Orellana's ship was separated from the main force. In one of the most improbably successful voyages in known history, Orellana managed to sail the length of the Amazon River, arriving at the river's mouth in 1541. However, his voyage was not without loss: just about every single one of his men died.

It was on this voyage that the Amazon got its name; Orellana wrote that he was attacked by fierce female warriors, but it is possible that he actually fought long haired male Amerindian warriors.

Orellana died on a subsequent voyage down the Amazon.

He today has a province of Ecuador (Orellana) named after him.