A coupe rear-ended a Ford Explorer, causing the Explorer to overturn around 9:30 p.m. at North First Street on the eastbound side of the highway, San Jose Fire Capt. Barry Stallard.
A male and female in their late teens or early 20s were in the Explorer and pronounced dead at the scene, Stallard said.
Four children, ages 5 to 15, were also in the Explorer and transported to local hospitals in critical condition, Stallard said.
Two people were in the coupe and were not seriously injured, according to Stallard.
All lanes of eastbound Highway 237 were shut down until just after midnight, according to the California Highway Patrol.