Energy absorptions under ballistic impacts of aramid fiber-reinforced poly(benzoxazine-co-urethane) composites at urethane mass concentrations of 0, 10, 20, 30, and 40 wt.% were investigated. The energy absorption of the composite was investigated by subjecting eight plies of the specimen with 9 mm and .44 Magnum according to levels II and IIIA of the National Institute of Justice standard-0101.04. The composite having the urethane mass concentration of 20 wt.% exhibited the synergistic behavior in energy absorption at both levels II and IIIA. The 20 wt.% of PU composite also possessed the greatest tensile strength and modulus. The numerical prediction revealed that the ballistic limit of aramid fiber-reinforced poly(benzoxazine-co-urethane) ballistic panel was as high as 690 m s −1 . High energy absorption capabilities of the composites can be tailored for fabricating the ballistic panels in soft armor applications.