Dutch prince of Nassau-Dietz and of Orange and stadtholder of the provinces of Friesland and Groningen, whose rejection as stadtholder by five of the seven Dutch provinces in 1702 marked the return to political supremacy of the States General (national assembly).

The son of Henry Casimir II, stadtholder and captain general of Friesland and Groningen, and Henriëtte Amalia of Anhalt-Dessau, John William succeeded to his father's titles in 1696. Although his cousin, the stadtholder William III, prince of Orange (William III as king of England after 1689), named John William as successor to his titles in 1695, he was rejected as stadtholder general on William III's death in 1702, marking the beginning of the second stadtholderless period (1702–47) in Dutch history. His claim to William's possessions was also disputed by William's cousin Frederick I of Prussia.

John William served with distinction as a general against France in the War of the Spanish Succession (1701–14) and in 1709 married Maria Louise of Hesse-Kassel. He was on the verge of a settlement with Frederick I when he drowned while crossing the Hollands Diep en route to The Hague. His posthumous son, William IV, prince of Orange-Nassau, became stadtholder of the Netherlands in 1747.