Manihi is a coral atoll in the Tuamotu Archipelago. It is one of the northernmost of the Tuamotus, located in the King George group.

Its oval-shaped lagoon measures about 10 km (6 mi.) across and 20 km (12 mi.) long, and is ringed by innumerable islets. The atoll is today home to a great number of pearl farms, and is the original home of the highly prized Polynesian black pearls. Several of the islands are inhabited, by populations ranging from single individuals to as many as 400.

The chief village, Turipaoa is located in the southwestern part of the atoll, and is home to about 400 inhabitants. The atoll's only airfield, served by the local Polynesian Airlines, is located here.

On Manihi are located two ancient ceremonial platforms (marae in Tuamotuan ), constructed of blocks of coral.

The lagoon is well-known among snorkelers for its beautiful and diverse marine fauna, including, among other species, the manta ray.