Okinawa Prefecture (沖縄県, Japanese: Okinawa-ken) is a prefecture of Japan. Okinawa Prefecture is the southernmost and westernmost prefecture of Japan and has a population of 1,457,162 (as of 2 February 2020) and a geographic area of 2,281 km² (880 sq mi).

Naha is the capital and largest city, with other major cities including Okinawa, Uruma, and Urasoe. Okinawa Prefecture encompasses two thirds of the Ryukyu Islands, including the Okinawa, Daitō and Sakishima groups, extending 1,000 kilometres (620 mi) southwest from the Satsunan Islands of Kagoshima Prefecture to Taiwan (Hualien and Yilan Counties). Okinawa Prefecture's largest island, Okinawa Island, is the home to a majority of Okinawa's population. Okinawa's indigenous ethnic group are the Ryukyuan people, who also live in the Amami Islands of Kagoshima Prefecture.

Okinawa was ruled by the Ryukyu Kingdom from 1429 and unofficially annexed by Japan after the Invasion of Ryukyu in 1609. Okinawa was officially founded in 1879 by the Empire of Japan after seven years as the Ryukyu Domain, the last domain of the Han system. Okinawa was occupied by the United States during the Allied occupation of Japan after World War II and was governed by the Military Government of the Ryukyu Islands from 1945 to 1950 and Civil Administration of the Ryukyu Islands from 1950 until the prefecture was returned to Japan in 1972. Okinawa comprises just 0.6 percent of Japan's total land mass, but about 26,000 (75%) of United States Forces Japan personnel are assigned to the prefecture; the continued U.S. military presence in Okinawa is controversial.