The Sierra de Guara is a mountain massif in the province of Huesca, the most northerly province in the autonomous community of Aragon, Spain. Its highest point is Tozal de Guara (2,077 m).
It lies around 25 km northeast of the city of Huesca itself. Much of the massif is now included within the Sierra y Cañones de Guara Natural Park which extends 43 km from west to east and 25 km north to south. The Park includes, in addition to the Sierra de Guara itself, much of the Sierra de Gabardiella in the west and the Sierra de Arangol, Sierra de Balced, Sierra de Sebil and Sierra de Rufás in the east.
A number of rivers flow north-south through the area, the principal ones having their sources to the north of the massif and cut through the range by way of spectacular gorges such as those of the Rio Alcanadre, Rio Guatizalema, Rio Vero and Rio Isuala. Each of these rivers ultimately drain into the Ebro.