William Henry Cornwell (May 30, 1843 – November 18, 1903) was an American businessman, as well as a military colonel and politician of the Kingdom of Hawaii.

He served two separate terms as Minister of Finance and was a member of Queen Liliuokalani's last cabinet before the Overthrow of the Kingdom of Hawaii.

He was born in Brooklyn, New York, and relocated to Hawaii at an early age with his family where they became involved in sheep ranching in Waimea.

He formed a partnership with James Louzada for a sugar cane plantation on Maui, which was later sold to Claus Spreckels.

[1] Cornwell held the rank of Major and later Colonel, as a staff member under both King Kalākaua and Queen Liliuokalani.