Philochorus of Athens was a historian and religious expert who lived during the 3rd century BCE, a period of Macedonian rule following Alexander the Great. He was a member of a priestly clan associated with the Eleusinian Mysteries and served Athens as an official interpreter of religious law and omens. According to ancient reports, he was executed around 260 BCE by the Macedonian king Antigonus II Gonatas for his political sympathies toward the rival Ptolemaic dynasty of Egypt.

He was a prolific writer, though none of his works survive intact. They are known only through quotations by later authors. His most important work was the Atthis, a comprehensive history of Athens and the Attic region in at least seventeen books. He also wrote specialized studies on topics like divination, sacrifices, festivals, and religious mysteries.

Philochorus is considered the last and most significant figure in the tradition of "Atthidography," the writing of local Athenian history. His Atthis became the standard authoritative reference on Athenian antiquities, myth, and institutions for later scholars and historians. Modern scholars view the surviving fragments of his work as invaluable evidence for understanding Athenian chronology, political history, and religious practices.