Aesop's Fables are a series of moralized animal stories, written originally in the sixth century BCE and added to ever since. Little is known about Aesop, the original writer of the tales, other than that he was a Greek from Thrace and the island of Samos, and was a slave through captivity. He was the clerk and personal agent of his owner, and was known for his wit. While Aesop was the originator of the Fables, many of those now known were not written by him. Early references to Aesop and the Fables appear in the writings of Aristophanes (fifth century BCE), Plato and Aristotle. The scholars of the school of Aristotle took a particular interest in the Fables; one of them, Demetrius, produced a Greek edition containing about 100 episodes.

Aesop's Fables in various forms were known in the Middle Ages; manuscript copies still exist. Some of the animal characteristics described in the Fables are repeated in the bestiary (see ape, beaver, dog, hyena, lion, swan).

The Perry Index episode numbering system is used on this site. The Perry Index was developed by Ben Edwin Perry to organize the many fables; the Index lists over 700.