The paper introduces the essential features of a new strategy to develop reliable and computa-tionally cost-effective models of the mechanical response of a rockfall barrier subjected to realistic impact conditions. The approach combines the use of three-dimensional, non-linear and dynamic finite element models of a rockfall barrier with a reliability-based probabilistic approach. The strategy may apply to any type of rockfall barrier in presence of any condition of impact and it is devised so it can be implemented in rockfall propagation simulation tools. Applications of the approach are wide and includes the evaluation of the residual hazard down existing protection works and the reliable planning of new interventions.