The US Army Tank Automotive Research, Development and Engineering Center (TARDEC) developed a unique physics based modeling & simulation (M&S) capability using Computational Fluid Dynamics (CFD) techniques to optimize Automatic Fire Extinguishing System (AFES) designs and complement vehicle testing for both occupied and unoccupied spaces of military ground vehicles. The modeling technique developed here is based on reduced global kinetics for computational efficiency and is applicable to fire suppressants that are being used in Army vehicles namely, bromotrifluoromethane (Halon 1301), heptafluoropropane (HFC-227ea, trade name FM200), sodium bicarbonate (SBC) powder, water + potassium acetate mixture, and pentafluoroethane (HFC-125). These CFD simulations are performed using High Performance Computers (HPC) that enable the Army to assess these designs inexpensively in a virtual world that is crucial for vehicle and soldier protection in this complex world. This methodology is applied to vehicle crew compartments for multiple scenarios using FM200+SBC which is the predominant suppressant combination used in most US combat and tactical vehicles. Predicted results match qualitatively very well for overall time for suppression and results are also evaluated for soldier survivability from thermal injury, blast overpressure and inhalation toxicity risks. After gaining confidence with crew compartment simulations, this fire suppression modeling methodology is now being applied to the geometrically-more-complex military vehicle engine compartment. Simulations studies will be presented with HFC-125 fire suppressant that is widely used for fire suppression in unoccupied spaces such as engine compartments. Challenges associated with the fire suppression simulations are discussed along with future developments that are being proposed to enhance the overall accuracy of the simulation methodology. Applicability of the military ground vehicle fire suppression framework for civilian automotive vehicle applications will be highlighted.