The Russian ironclad Petropavlovsk (Russian: Петропавловск) was a 22-gun armored frigate in the Imperial Russian Navy during the late 19th century. She was originally ordered as a 58-gun wooden frigate, but she was reordered as an ironclad while under construction and subsequently converted into one. She served as the flagship of the Baltic Fleet during the 1860s and 1870s. The ship was decommissioned in 1885, but was not sold for scrap until 1892.