Israel Regardie (November 17, 1907 - March 10, 1985) was an occultist. He was born in London.

He became Aleister Crowley's secretary in 1928. In 1932 Crowley and Regardie parted company. Both had been leading members of the Hermetic Order of the Golden Dawn.

When the Golden Dawn disbanded, Regardie took the bulk of the Order's documents and compiled the book, The Magical System of the Golden Dawn, which earned him the enmity of the other former members and the reputation of being an oath-breaker. However, the book transformed the work of the Order into an entire new branch of the Western Occult Tradition. The various occult organizations claiming descent from the original Golden Dawn and the systems of magic practiced by them owe their continuing existence and popularity to Regardie's work. Other books include A Garden of Pomegranates, The Middle Pillar, and The Tree of Life.

He died in Sedona, Arizona.