Abstract: A modular vehicle frame structure assembly, which combines a monocoque cabin structure with separately attachable space frame structures, is disclosed. The modular vehicle body assembly includes a monocoque cabin structure, a front frame section and a rear frame section, wherein the front and rear frame sections secure separately to the respective front and rear sections of the cabin structure and extend longitudinally therefrom forming a modular vehicle body with the cabin structure. The modular vehicle frame assembly is useful in the construction of light weight, low-profile military vehicles.