National Park Service officials say they got a report of the crash on Northshore Road about 6 p.m. Sunday.
Witnesses say the vehicle was traveling north near mile marker 23 when the driver attempted to pass another vehicle in a no-passing zone. Officials say the vehicle rolled three times.
One person was pronounced dead at the scene, while the other was taken to the hospital by helicopter in critical condition.
Nevada Highway Patrol officials are investigating. The names of the victims have not yet been released.