Police, fire, ambulance and the air ambulance were all called to the M1 southbound in Northamptonshire at around 7.42am.
There has been an accident involving a lorry between junction 15 and 16, with drivers facing long delays.
Thames Valley Police are dealing with the incident, with assistance from Northamptonshire Police.
A spokesman for Thames Valley said: “A lorry has come off the carriageway. We don’t know how or why at the moment. Two lanes are currently closed.
“The lorry driver is injured and it’s potentially serious.”