Pegasus Bay is on the east coast of the South Island of New Zealand.

The bay has a sandy beach and runs from Banks Peninsula to the Waipara River mouth. The city of Christchurch is at the southern end of the bay.

The Pegasus was the name of the sailing ship which surveyed part of the South Island in 1809. The first mate of the brig Pegasus, William Stewart, gave Pegasus Bay its name. The captain of the ship, Captain S. Chase, lays claim to correcting James Cook charts by determining that "Banks Island" was in fact a peninsula.