Abstract: In combination, a foldable door assembly and sliding window assembly for vehicles is disclosed. The combination allows the driver of the vehicle to see through the window assembly, open it, and adjust a rearview mirror allowing operation of the vehicle with the foldable door to be in the closed position. The door assembly has a first section and a second section hingeably connected to one another. The second section rotates and folds against the first section. The first section has a rear edge hingeably connected to a truck body so that the first section of the door assembly rotates to an open position onto the truck body from a closed position. The first section defines an opening for placement of a frame having a track which holds a sliding window.