Avvakum Petrov (November 20, 1620 or 1621 – April 14, 1682) is a Russian protopope of Kazan Cathedral on Red Square who leads the opposition to Patriarch Nikon's reforms of the Russian Orthodox Church.

His autobiography and letters to the tsar, Boyarynya Morozova and other Old Believers are considered masterpieces of 17th-century Russian literature.