Transverse loading of grid-stiffened composite panels has significance in automotive crashworthy applications where optimizing the energy absorption is stipulated along with weight-critical restrictions. The phenomenon of failure and energy absorption in composites is complicated and this research is just a beginning to understand the behavior of grid stiffened composites under transverse quasi-static and dynamic load conditions. Authors, in their earlier publications have studied the energy absorption capabilities of E-glass/Polypropylene (PP) isogrid-stiffened composite panels under transverse loading, experimentally and validated the results using finite element analysis. The concluding part of this research is presented here which involves parametric studies of optimizing the grid geometry for maximizing the specific energy absorption under transverse quasi-static and dynamic impact loading. The parametric variations of skin thickness; width and thickness of ribs; and center-to-center distance between rib joints are performed in finite element analysis to maximize the specific energy absorption under transverse quasi-static and dynamic impact loading. The findings of this study will provide an optimized geometry of grid-stiffened composite panels which can impart highest specific energy absorption under transverse loading. This study will help in recommending the design and use of grid-stiffened composite panels in applications where impact energy absorption is important such as in the side doors of automobiles and highway side guardrails.