The crash happened just after 9:30 p.m. on Northbound Route 13 near Lisa Drive in New Castle City.
Police say the driver of an SUV lost control of the vehicle sending it flipping over several times.
Some of the occupants were ejected.
One person was pronounced dead at the scene.
Two others were taken to area hospitals with life-threatening injuries.
A third person was hospitalized with non-life-threatening injuries.
Two others in the SUV were unharmed.
Delaware State Police are investigating whether alcohol may have been a factor in the crash.