Greater sage-grouse (Centrocercus urophasianus; hereafter sage -grouse), a galliform bird native to sagebrush steppe ecosystems of western North America, have experienced substantial population declines and range contraction in recent years. In the American West, several non-native galliform species have distributions that overlap sage-grouse, creating potential competition for nest and brood sites. While interspecific nest parasitism has been documented in sage-grouse previously, no observations of parasitic chicks within sage-grouse broods have been reported, to our knowledge. Here, we describe the first documented case of parasitism by chukar (Alectoris chukar), an introduced galliform bird from Eurasia, on a sage-grouse nest and brood in western Nevada in 2023. Because nest parasitism has been shown to have negative effects on nest success in other galliform species, our observation indicates that further investigation of interspecific nest and brood parasitism occurrence and effects on sage-grouse could help inform their conservation and management. This information is preliminary, subject to change, and provided for best timely science.