Willem V of Horne

Willem V of Horne (c. 1337–1357) was the eldest son of Willem IV of Horne. After his half-brother Gerard II fell at Warns in 1345, his uncle Dirk of Perwez secured him the lordships of Horne, Kortessem and Weert as fifth lord of Horne, while his half-sister Johanna took the Brabant lands. Holland granted him the fief of Altena in 1347.

In 1349 he married Machteld, daughter of John IV of Arkel. He was dead by April 1357, when Altena passed to his brother Dirk Loef.