The Senegal River (Arabic: نَهر السنغَال, romanized: Nehr es-Sinigâl, French: Fleuve Sénégal, Wolof: Dexug Senegaal) is a 1,086 km (675 mi) long river in West Africa; much of its length marks part of the border between Senegal and Mauritania. It has a drainage basin of 270,000 km² (100,000 sq mi), a mean flow of 680 m³/s (24,000 cu ft/s), and an annual discharge of 21.5 km³ (5.2 cu mi). Important tributaries are the Falémé River, Karakoro River, and the Gorgol River. The river divides into two branches once it passes Kaédi The left branch, called the Doué, runs parallel to the main river to the north. After 200 km (120 mi) the two branches rejoin a few kilometers downstream of Podor.

In 1972 Mali, Mauritania and Senegal founded the Organisation pour la mise en valeur du fleuve Sénégal (OMVS) to manage the river basin. Guinea joined in 2005. As of 2012, only very limited use was made of the river for the transportation of goods and passengers. The OMVS have looked at the feasibility of creating a navigable channel 55 m (180 ft) in width between the small town of Ambidédi in Mali and Saint-Louis, a distance of 905 km (562 mi). It would give landlocked Mali a direct route to the Atlantic Ocean.

The aquatic fauna in the Senegal River basin is closely associated with that of the Gambia River basin, and the two are usually combined under a single ecoregion known as the Senegal-Gambia Catchments. Only three species of frogs and one fish are endemic to this ecoregion.

The river has two large dams along its course, the Manantali Dam in Mali and the Maka-Diama Dam downstream on the Mauritania-Senegal border. In between is the Félou Hydroelectric Plant, built in 1927, but replaced in 2014. The construction of the Gouina Hydroelectric Plant upstream of Felou at Gouina Falls began in 2013.