West Sussex Fire and Rescue Service said crews attended the fire in Manning Road, Wick, Littlehampton at 3.40am this morning (Sunday).
A spokesman said: "Four cars were alight. Three were destroyed and another one was damaged by the deliberate ignition.
"Crews used two breathing apparatus', two high pressure hose reels.
"Crews left at 4.48pm."
Sussex Police confirmed it attended the scene after reports of a vehicle fire 'which had spread to other cars'.
A spokesman said: "Four cars were alight when we got there. We recovered what was left of the vehicles.
"An investigation is underway."