The Bosut (Serbian Cyrillic: Босут) is a river in the Syrmia region of eastern Croatia and northwestern Serbia.

The narrow riverbed widens in Cerna where the Bosut receives the water of the Biđ, a 66 km (41 mi) long tributary originating in central Slavonia region, on the southern slopes of the Dilj mountain.

The outflow named Bosut was created in the last bend of the great meanders of the Sava, and the surges of water caused the flow to stretch all the way to Vinkovci.

[6] Turning north from Cerna, the river flows into the region of Syrmia, and the villages of Andrijaševci and Rokovci, reaching the biggest settlement on its course, the city of Vinkovci.

It passes through Kunjevci, Nijemci, Podgrađe, Apševci and Lipovac, where it receives the river Spačva from the right, and after the flow of 151 km through Croatia,[2] crosses the Serbian border.

[11][3] Due to such a flow, the river has a specific ecosystem, abundant in fish,[7] marsh plants and a deep deposit of silt from their rotting.