Green Turtle Cay is one of the barrier islands off mainland Great Abaco The Bahamas. It is considered part of the "Abaco Out Islands" and is 3 miles (4.8 km) long and ½ mile wide. It was named after the once abundant green turtles that inhabited the area.

The population of the island is about 450 and its main settlement is New Plymouth which was founded in the 18th century. The architecture of the older homes in the village is unique in the Bahamas, with steep-pitched roofs, originating with settlers from New England. New Plymouth contains a post office, a bank, a customs and immigration office, four grocery stores, several restaurants, bars, and churches and there is a museum featuring the paintings of noted Bahamian painter Alton Lowe. The village can be walked in less than 15 minutes end to end. While cars are allowed on the island, golf carts and bicycles are the usual mode of transport. Both are easily rented for those visiting the island.

Green Turtle Cay is known for its beaches and has several full-service hotel-resorts with boat marinas. These are Bluff House and the Green Turtle Club. There is also a boat repair yard with haul-out slips. Green Turtle Cay is a stopover-point for southbound vessels during periods of rough seas in the Whale Cay Passage. Lobstering and tourism are the main industries of the island today.