The probability of damage at the impact site in the outer glass ply of laminated glass units subjected to low velocity small missile impacts is investigated. A dynamic, non-linear finite element analysis is applied to compute the stress response on impacts. Based on the cumulative damage theory, a damage factor is introduced and related to Weibull＇s distribution of probability to characterize the probability of damage. In conjunction with the finite element analysis, controlled experiments are conducted to determine the material constants appearing in the damage model and Weibull＇s distribution of probability. A parametric study involving impact velocity, glass ply thickness and interlayer thickness is presented.