The short-tailed river stingray (Potamotrygon brachyura) is a species of river stingray (family Potamotrygonidae) native to the Río de la Plata Basin in South America. It is sometimes known as the giant freshwater stingray, but this name is typically used for Urogymnus polylepis.

Growing to a disc diameter of about 1.9 m (6.2 ft) and a weight of 220 kg (485 lb 0 oz), with unconfirmed records of even larger specimens, the short-tailed river stingray is the largest freshwater species in its family and one of the heaviest strict freshwater fish in South America, only matched by the arapaima (Arapaima) and piraíba catfish (Brachyplatystoma filamentosum). The primary threat to the short-tailed river stingray is fishing for food and as a game fish (if not released), but it is also under pressure from habitat loss and occasionally caught for aquaria.

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