Petrof Bay is a small bay on the west side of Kuiu Island in the Alexander Archipelago in southeastern Alaska, United States. It is located at and opens into the Chatham Strait. <!-- The long was originally 134°5', when someone gets sufficiently detailed info to use coor dm or coor dms -->
The bay was named in 1924 for U.S. Census Bureau employee Ivan Petrof, whose reports of his travels in the late 19th century are a valuable source of Alaska history for that period.
The US Navy aircraft carrier USS Petrof Bay, launched in January 1944, was named after it.