Abstract: A stair system for providing access to a cargo platform of a commercial vehicle is disclosed. The stair system is movable between a deployed configuration and a stowed configuration. The stair system comprises a mounting plate, a stair assembly, and a linkage assembly. The mounting plate is configured to be attached to the cargo platform of the commercial vehicle. The stair assembly includes a top platform that is slidably received within the mounting plate and a plurality of step platforms that is pivotally attached to the top platform. The linkage assembly comprising at least one slotted link that includes a slot and at least one first link that is slidable relative to the slot. When in the stowed configuration, the stair system is configured to be positioned beneath the cargo platform. When in the deployed configuration, the stair system is configured to extend outwardly from the cargo platform.