The Aliʻi nui of Maui was the supreme ruler of the island of Maui, one of the four main Hawaiian Islands. The title is the same as that of the Aliʻi nui of the other islands. The title or phrase Mōʻī is sometimes used for the title of the monarchs of Maui; however, it is not an ancient word in the Hawaiian language and has origins in the mid 19th century. The only monarchs to officially hold the title of Mōʻī are Kalākaua and his sister Liliuokalani.
The monarchs of Maui, like those of the other Hawaiian islands, claim descent from Wākea and Papa. They were sometimes referred to as Mōʻī beginning in the mid 19th century, and would later become commonly translated from the Hawaiian language into English as the word "king".Paumakua, the first ruler of Maui, was thirty-first in line of descent from Wakea. In the beginning, from about Paumakua of Maui down to Kawaokaohele's reign, the Aliʻi nui of Maui only controlled the much larger western portion of the island while the chiefs of Hana remained independent. Mauiloa had tried to unite the island once, but troubles with the Hana chief continued. It was under Piʻilani's reign that he conquered the east and united Maui for the first time.
Kahekili II expanded his empire by conquering the neighbouring island of Oʻahu in 1783 and through marriage of his brother allied himself with the Queen of Kauaʻi. However, his son Kalanikūpule was the last of his line. Maui was weakened when Kalanikupule and his uncle, Kaeokulani, fought over the succession to the throne. Maui along with Oʻahu fell to Kamehameha I in 1795 and ushered in the Kingdom of Hawaii.