thumb|right|350px|Sagebrush steppe with [[Artemisia tridentata, of the Great Basin region in Owyhee County, Idaho]]
Sagebrush steppe also known as the sagebrush sea, is a type of shrub-steppe, a plant community characterized by the presence of shrubs, and usually dominated by sagebrush, any of several species in the genus Artemisia. This ecosystem is found in the Intermountain West in the United States.
The most common sagebrush species in the sagebrush steppe in most areas is big sagebrush (Artemisia tridentata). Others include three-tip sagebrush (Artemisia tripartita) and low sagebrush (Artemisia arbuscula). Sagebrush is found alongside many species of grasses. It is key habitat for declining flora and fauna species, such as greater sage-grouse (Centrocercus urophasianus) and pygmy rabbit (Brachylagus idahoensis).
Sagebrush steppe is a threatened ecosystem in many regions. It was once prevalent in the regions that form the Intermountain West such as the Great Basin and Colorado Plateau. It has become fragmented and degraded by many forces. Cheatgrass (Bromus tectorum) is also an important introduced plant species that increases fire risk in this ecosystem. Other forces leading to these habitat changes include fire suppression and overgrazing of livestock.