OSP says the crash occurred around 3:40 p.m. Sunday on Highway 26 about 30 miles from Vale, Ore., in Malheur County.
Investigators say Courtney Glick-Peterson, 31, and her husband, Zachary Peterson, 26, of Boise died at the scene.
OSP says Courtney Glick-Peterson was driving when the vehicle entered a right curve and traveled into the westbound lane and collided with a pickup truck hauling an empty livestock trailer driven by Eugene Bernard, 76, of Paulina, Ore. Bernard also died at the scene.
Zachary was not wearing a seatbelt and was ejected from the vehicle.
OSP is still investigating whether the drivers wore seatbelts.