Eupithecia osornoensis is a moth in the Geometridae family. It is found in the Region of Los Lagos (coastal Osomo Province) in Chile. The habitat consists of the Valdivian Forest Biotic Province. The length of the forewings is about 9 mm for males and 8 mm for females. The forewings are pale grey with medium and dark brown scaling. The hindwings are paler than the forewings, becoming darker distally. Adults have been recorded on wing in February.