Molokai (ˌmoʊloʊˈkaɪ) (Hawaiian: Molokai ˈmoloˈkɐi, ˈmoloˈkɐʔi) is the fifth most populated of the eight major islands that make up the Hawaiian Islands archipelago in the middle of the Pacific Ocean. It is 38 by 10 miles (61 by 16 km) at its greatest length and width with a usable land area of , making it the fifth-largest in size of the main Hawaiian Islands and the 27th largest island in the United States. It lies southeast of Oahu across the wide Kaʻiwi Channel and north of Lānai, separated from it by the Kalohi Channel.
The island's agrarian economy has been driven primarily by cattle ranching, pineapple production, sugarcane production and small-scale farming. Tourism comprises a small fraction of the island's economy, and much of the infrastructure related to tourism was closed and barricaded in the early 2000s when the primary landowner, Molokai Ranch, ceased operations due to substantial revenue losses. In Kalawao County, on the Kalaupapa Peninsula on the north coast, settlements were established in 1866 for quarantined treatment of persons with leprosy; these operated until 1969. The Kalaupapa National Historical Park now preserves this entire county and area. Several other islands are visible from the shores of Molokai, including Oahu from the west shores; Lanai from the south shores, and Maui from the south and east shores.
The island is known under several names by the local population: Molokai Āina Momona (land of abundance), Molokai Pule Oo (powerful prayer), and Molokaʻi Nui A Hina (of the goddess Hina).
Both the form Molokai (without an okina) and Molokai (with) have long been used by native speakers of Hawaiian, and there is debate as to which is the original form, with conflicting claims as to which the elders used.
The USGS uses the form with the okina.
Molokai developed from two distinct shield volcanoes known as East Molokai and the much smaller West Molokai. The highest point is Kamakou on East Molokai, at . Today, East Molokai volcano, like the Koolau Range on Oahu, is what remains of the southern half of the original mountain.