Abstract: A vehicle fuel door and sliding side door interlock mechanism to prevent the sliding side door from being opened when the fuel door is open. The interlock includes a latch mechanism mounted on the pillar, a striker secured to the rear edge for closing and opening cooperation with the latch mechanism, an arm secured to the fuel inlet door, a blocking lever operatively connected to the latch mechanism adaptable to block the operation of the latch mechanism, and a linkage operatively connected between the arm and the blocking lever for actuating the blocking lever to prevent the latch mechanism from being opened past the striker and, thereby, prevent the side door from being opened when the fuel inlet door is open.