Vehicle side panel storage box assembly

A vehicle side panel storage box assembly (12) has a mounting structure (30), a compartment (32) and a side panel door (34). The mounting structure (30) is fixedly coupled to a pair of lateral cross frames (24) of a vehicle body and has the side panel door (34) pivotally mounted to the mounting structure (30). The compartment (32) is fixedly coupled to the mounting structure (30) as a modular unit. The side panel door (34) has an exterior surface panel configured and arranged to form an exterior of a vehicle body side panel.