Sven (in Danish and Norwegian, also Svend and also in Norwegian most commonly Svein) is a Scandinavian first name which is also used in the Low Countries and German-speaking countries, and is cognate with the English name Swain. The name itself is Old Norse for "young man" or "young warrior". The original spelling in Old Norse was sveinn.

Many northern European rulers have carried the name including Sweyn I of Denmark (Sven Gabelbart). An old legend relates the pagan king Blot-Sven ordered the execution of the Anglo-Saxon monk Saint Eskil.

In medieval Swedish, "sven" (or "sven av vapen" (sven of arms)) is a term for squire. The female equivalent, Svenja, though seemingly Dutch and Scandinavian, is not common anywhere outside of German-speaking countries. Sven can also be spelled with W, Swen, but is pronounced as Sven.

The Icelandic version of Sven/Svend is Sveinn (Icelandic pronunciation: ​[ˈsveitn̥]); the Faroese version is Sveinur (Faroese pronunciation: [ˈsvaiːnʊɹ]).