Monas Hieroglyphica is a book by John Dee, the Elizabethan magus and court astrologer of Elizabeth I of England, published in Antwerp in 1564. It is an exposition of the meaning of an esoteric symbol that he invented.

John Dee was an English mathematician, astronomer, teacher, astrologer, occultist, and alchemist. He was the court astronomer for, and advisor to, Elizabeth I, and spent much of his time on alchemy, divination, and Hermetic philosophy. As an antiquarian, he had one of the largest libraries in England at the time. As a political advisor, he advocated the foundation of English colonies in the New World to form a "British Empire", a term he is credited with coining.