This chapter presents the impact response of double-layer steel-rubberized ultra-lightweight cement composite (RULCC)-steel sandwich panels via experimental, numerical, and analytical approaches. Seven full-scale panels are tested under drop-hammer impact with different concrete layers, degree of composite action (connector spacing/type), and rubber content. The middle steel plate spreads the load and reduces penetration by 11% compared to single-layer specimen. RULCC cores with 5% rubber volume improve energy absorption and crack control compared with ULCC. Steel and concrete synergistically dissipate >95% of the impact through steel yielding and concrete cracking. Panels with partial composite action, i.e., larger connector spacing are more flexible and can exhibit higher impact resistance with a slight reduction in residual flexural capacity. An LS-DYNA model accurately simulates both impact and post-impact behavior with excellent agreement with experimental results. Single-degree-of-freedom (SDOF) and two-degree-of-freedom (TDOF) models are developed to predict the impact response. The SDOF model tends to overpredict peak displacement when the hammer mass greatly exceeds the effective panel mass, whereas the TDOF model more accurately captures peak force, peak displacement, and residual deformation. The results support double-layer panels with RULCC cores, controlled composite action, and increased face-plate thickness for protective applications under single and repeated impacts.