The Uzh (Ukrainian: Уж; translit. Uzh; Slovak: Uh; Hungarian: Ung, Polish: Uż) is a river in Ukraine and Slovakia. Etymologists disagree about the origin of the name of the river.

The Uzh is a tributary of the Laborets River, a river that flows in the Tysa Lowland in Zakarpattia Oblast of western Ukraine. The river feeds numerous industries and is a source of drinking water and irrigation. It also has a hydropower station on it. Several important cities lie along its course, including Uzhhorod.

It is 127 km (79 mi) long, of which 21.3 km (13.2 mi) are in Slovakia. It flows into the Laborec river near the city of Drahňov in the Michalovce District (okres).

The Ukrainian city of Uzhhorod and the semi-ruined Nevitske Castle are situated by the Uzh. The river forms part of the Slovakia–Ukraine border for about 1.5 km (0.93 mi) near the village of Pinkovce.

The Uzh is located in the Zakarpattia Oblast in Ukraine and in the districts of Michalovce and Sobrance in eastern Slovakia.

The largest tributaries are, Right: Ug [uk; ru], Strychavka, Ulychka, Ubľa, Kamyanitsa, Dvernitsky, Domaarach, Volshava, Syry Potyk, Hachnyk. Left: Unnamed, Velikiy [uk], Luta [uk], Tur'ya, Simoni [uk].

The meander is winding, moderately branched. There are low waterfalls and many islands.