The accident happened around 11:07 a.m. on Route 63 near Little Canada Road in the Town of Bethany.
35-year-old Peter Boyce, his wife Connie Boyce and their two children, 9-year old Alexander and 5-year old Bradley all died at the scene. The tractor trailer was carrying rolls of aluminum to Pennsylvania. Route 63 was closed for several hours.
Authorities are working to determine the cause of the crash.