Horapollo the Grammarian was a scholar from Egypt active in the 5th century CE during the late Roman Empire. He worked as a teacher in Alexandria, but historical sources record that he was forced to flee to Constantinople after being accused of participating in pagan rituals. To avoid further persecution, he reportedly converted to Christianity. His life illustrates the pressures faced by non-Christian intellectuals in the increasingly Christianized empire.

He is credited with authoring the Hieroglyphica, a two-book treatise written in Greek that explains Egyptian hieroglyphs. The work's authorship is uncertain; some scholars believe it was written by this 5th-century grammarian, while others suggest it may be a later compilation from the Byzantine period. Another work, On the Temples of Egypt and the Festivals Celebrated in Each, is attributed to him but is now lost.

Horapollo’s significance lies almost entirely in the influence of the Hieroglyphica. Although modern scholars understand that its interpretations of hieroglyphs as purely symbolic pictures were incorrect, the text became the standard reference on the subject for over a thousand years. It profoundly influenced Renaissance thought, emblem literature, and early attempts at Egyptology until hieroglyphs were finally deciphered in the 19th century. The work remains a key example of how ancient Egyptian culture was transmitted and interpreted by the later Greek-speaking world.