The Warnow (German pronunciation: [ˈvaːno]) is a river in the state of Mecklenburg-Vorpommern in Germany.

The source of the Warnow is in Grebbin, a small village 10 kilometres (6 mi) north of Parchim, at the western end of the Mecklenburg Lake District.

Recent work suggests a non-Indo-European (perhaps specifically Hattic) element ar(i)n ('spring, stream'), giving rise to the Slavic form Warnow through the prosthesis of /v-/.

The ancient geographer Claudius Ptolemäus mentioned a river around 150 CE whose location would correspond to the Warnow, which he called the Χαλοῦσος (Latin: Chalusus).

[3] Meanwhile, Arnold of Lübeck's Chronica Slavorum mentions that Berno, Apostle of the Obotrites 'pro Gutdracco Godehardum episcopum venerari constituit' ('instituted the veneration of Bishop Godehard in place of Gutdracco').