The Timiş or Tamiš is a 359 km long river rising in the Semenic Mountains, southern Carpathian Mountains, Caraş-Severin County, Romania. It flows through the Banat region and flows into the Danube near Pančevo, in northern Serbia.

In antiquity, the river was known as Tibiscus and Tibisis.

The drainage area covers 13,085 km² (Romania 8,085 km², Serbia 5,000 km²). With the Danube, it belongs to the Black Sea drainage basin. The river flows through Romania for 241 km, and 118 km through Serbia.

The river starts at the junction of headwaters Brebu, Grădiştea and Semenic in Lake Trei Ape. Barajul Trei Ape are 30 m inaltime

After entering Banat, the river becomes slow and meandering.

In its lower course, the river is regulated, and for the last 53 km it is navigable. The most important port is the heavily industrialized Pančevo.

After Banat, floods occur in rainy years. Especially devastating were the floods of 2005, when the villages Boka and Jaša Tomić were badly damaged. On April 20, 2005, a level of 844 centimeters was recorded, the highest ever since the measurements began.

In the spring of 2007 works on the elevation of the embankments on the both sides of the river began, 11.5 kilometers on the right bank and 13.2 kilometers on the left. The embankments will be 30 to 70 centimeters higher than they are now and being higher than 8.5 meters should prevent any future floodings.

In some parts of the low, marshy areas created by the floods, several fish-filled lakes have been created, most notably at Banatski Despotovac, Uzdin, Sakule and Slatina.

The following river is the major tributary to the river Timiş: Bârzava/Brzava.

Major cities in its Romanian course are Caransebeş and Lugoj.

Timişoara has its name derived from the river Timiş meaning the fortress Timiş and the Timiş City, even though its name indicates it, is not settled on the river, but on another Romanian-Serbian river, Bega.