Phrynops geoffroanus, also commonly known as Geoffroy´s side-necked turtle and Geoffroy´s toadhead turtle, is a species of large side-necked turtle in the family Chelidae. The species is endemic to South America.

Etymology: The specific name, geoffroanus, is in honor of French naturalist Étienne Geoffroy Saint-Hilaire.

Geographic range: P. geoffroanus is found in southwestern Venezuela, southeastern Colombia, eastern Ecuador, and eastern Peru, southward and eastward through southwestern Brazil and northern Bolivia to Paraguay and northeastern Argentina, then northward through eastern Brazil. It also occurs in eastern Venezuela, and in adjacent Guyana.

Habitat: The preferred natural habitat of P. geoffroanus is freshwater rivers.