Mazdak (died c. 524 or 528) is the chief representative of a religious and philosophical teaching called Mazdakism, which he views as a reformed and purified version of Zoroastrianism, although his teaching has been argued to display influences from Manichaeism as well.

Zoroastrianism is the dominant religion of Sassanid Persia, and Mazdak himself is a Zoroastrian priest, or mobed, but most of the Zoroastrian clergy regarda his teaching as heresy.

Information about it is scarce and details are sketchy, but some further details may be inferred from the later doctrine of Khurramism, which has been seen as a continuation of Mazdakism