Abstract: A fuel tank mounting and protective cage for vehicles such as school buses including side structures and a bottom shelf structure, each of these structures being weldments constructed of low carbon, high strength steel tubing having rectangular cross-sections. The bottom structure is connected to the side structures by bolt assemblies, preferably disposed in laterally offset parallel rows, to produce stiff joints between the sections with the result that there is less rotation and localized deformation of the protection cage in the event of an accident. Hold down devices are carried by the bottom shelf structure for securing the fuel tank directly to the bottom shelf structure so that the bottom shelf and fuel tank may be removed as a unit for service.