Târnava (Hungarian: Küküllő, German: Kokel) is a river in Romania, tributary to the river Mureş. It is formed by the confluence of the rivers Târnava Mare (Big Târnava) and Târnava Mica (Small Târnava) in the city Blaj. The Târnava flows into the Mureş after 28 km, near the city Teiuş.
The source of the Târnava Mica (Hungarian: Kis-Küküllő, German: Kleine Kokel) is also in the Eastern Carpathian Mountains, in the Romanian county Harghita. It flows through the Romanian counties Harghita, Mureş and Alba, more or less parallel to and north from the Târnava Mare. The cities Sovata and Târnăveni lie on the river Târnava Mica.
The geographical setting of the town is on the TarnavaMare river, at an average altitude of 320.5 m and at a distance of 56 km-s north-west of Sibiu.
At the entrance of the Tarnava river into the town the altitude is of 295.3 m, and at the exit the altitude decreases to 290 m.
The climate characteristics are determined by a number of elements such as the geographical setting of the town in a plateau area and in the corridor of the TarnavaMare river.