Emergency services rushed to the scene on the coastbound carriageway of the A2 near Gravesend on December 28.
Kent Police confirmed they were called at 12.14pm following reports of the crash.
Paramedics and fire crews also attended, with two people treated for injuries at the scene before being taken to a local hospital for further care.
All vehicles involved in the crash have now been recovered, but the carriageway remains closed as teams work to clear an oil spillage from the road surface.
Drivers are advised to avoid the area while clean-up operations continue.
A spokesperson for Kent Police said: “Kent Police was called at 12.14pm on Saturday 28 December to a collision involving four cars on the coastbound carriageway of the A2 near Gravesend.
“Officers, paramedics and fire crews attended the scene where two people were treated for injuries.
“They have been taken to a local hospital for further medical attention.
“All the vehicles have now been recovered and the carriageway remains closed currently while an oil spillage is removed from the road surface.