Koviljsko-Petrovaradinski Rit, Nature reserve along the Danube River in Vojvodina, Serbia.

The Koviljsko-Petrovaradinski Rit is a nature reserve covering about 4,800 hectares of wetlands, forests, and waterways along the Danube in southeastern Bačka. The landscape consists of channels, islands, and meandering river sections that create a complex pattern of water and land.

The area received official protection status in 1998, preserving one of the last remaining natural floodplains of the Middle Danube. This designation recognized the ecological importance of the river system and halted further changes from human activities.

The reserve's name links the villages of Kovilj and Petrovaradin on opposite banks of the Danube. Its floodplain forests and marshes have long been used for occasional grazing of livestock, a practice that continues alongside protection. The area is also a candidate for the Ramsar Convention list of wetlands of international importance.

The reserve is split into two sections: the right bank between Sremski Karlovci and Petrovaradin, and the larger left-bank stretch from Sremski Karlovci to Gardinovci. The Belgrade–Novi Sad motorway crosses the central part over a high Danube bridge. About 55% of the area is forest, and the three protection zones limit access.

The reserve protects two breeding pairs of White-tailed Eagles and an estimated 8–10 pairs of Black Storks, figures that gave the area its international standing. Its floodplain forests of white willow, almond willow, white and black poplar and ash also shelter the rare water chestnut (Trapa natans) and Hottonia palustris.