Police were called at 2.24pm on Tuesday (December 1) to reports of a collision involving a silver Toyota Yaris and a blue Ford Fiesta.
A 44-year-old man from Tunbridge Wells was pronounced dead at the scene. A woman was also taken to the Royal Sussex County Hospital in Brighton with serious injuries.
The A26 was closed for around six hours while emergency services attended the scene.
Anyone who saw what happened, saw either vehicle being driven prior to the collision or who may have any relevant dash cam footage is asked to get in touch.
People can contact police online or by calling 101 quoting Operation Prime.