| William Henry of Nassau-Usingen | |
| Noble Family: | House of Nassau |
| Father: | Walrad, Prince of Nassau-Usingen |
| Mother: | Catherine Françoise, comtesse de Croÿ-Roeulx |
| Spouse: | Charlotte Amalia of Nassau-Dillenburg |
| Birth Place: | 's-Hertogenbosch |
| Death Place: | Usingen |
Prince William Henry of Nassau-Usingen (born 2 May 1684 in 's-Hertogenbosch; died: 14 February 1718 in Usingen) was Prince of Nassau-Usingen from 1702 to 1718.
William Henry was the son of Prince Walrad of Nassau-Usingen and his wife, Catherine Françoise, comtesse de Croÿ-Roeulx.
William Henry married Charlotte Amalia (1680–1738), daughter of Henry, Prince of Nassau-Dillenburg, on 15 April 1706. They had nine children, five of which died within the first year: Henry (1708–1708), Amélie (1709–1709), William (1710–1710), Louis (1714–1714), and Johanna (1715–1716). Four children reached adulthood:
After he died in 1718, he was succeeded by his underage son Charles as Prince of Nassau-Usingen. Charlotte Amalie reigned as regent until Charles came of age.
In 1707, William Henry founded the village of Wilhemsdorf, which was named after him. It was annexed by neighbouring Usingen in 1972.
Like his father, William Henry had a career in the Dutch army. In 1691, he became a captain and then the colonel of the Walloon Regiment from 1701 to 1707. He was wounded in the Battle of Ekeren on 30 June 1703.