The Dusky-legged Guan (Penelope obscura) is a species of bird in the Cracidae family, the chachalacas, guans, and curassows. It is found in southernmost Brazil, northern Uruguay, Paraguay, and northeastern Argentina; a narrow disjunct range is in northern Argentina extending into south-central Bolivia.

Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montanes. The bird measures an average of 73 centimeters in length and weighs an average of 1.2 kilograms, being very similar in appearance to its smaller relative, the Rusty-margined Guan (P. supercilliaris). Eats fruit, flowers and buds taken from the ground or plucked from tree branches, and acts as a seed disperser for various species of trees and palms, such as the endangered palm Euterpe Edulis, or the palms of the Syagrus genus (e.g. Queen Palm and Licuri).