Sheriff's Department Captain Mark Helms says the crash occurred yesterday evening on Route 13 about 40 kilometers south of Syracuse.
Helms said seven of the eight passengers in the minivan died. The eighth person's condition was unknown.
Helms said two people in the tractor-trailer were not injured. He said a section of Route 13 has been closed in both directions while police investigates the matter.
Around the time of the accident, thunderstorms and steady showers with hail had moved through the area.