Abstract Gabion walls are considered to be novel, easy-to-transport, and rapidly deployable blast walls. They are widely used to protect military and civilian personnel and equipment in a variety of settings, such as humanitarian and peacekeeping operations. To study the protective effects of gabion wall against blast waves from large TNT-equivalent explosions, overpressure measurements are performed around gabion walls with 1 t and 10 t trinitrotoluene (TNT)ground explosion loads in this study. The effects of the stand-off distance and wall height on the back-wall overpressures are analyzed. Numerical simulations are also performed, and the results are validated by comparison to the experimental data and ConWep calculations. It is found that the height and blast distance of the walls are important factors for blast-wave attenuation compared to the wall thickness and wall material. The location where the Mach wave forms behind the wall is determined. An empirical equation that characterizes the blast mitigation efficacy of the gabion walls is derived based on the findings of this study. The findings from this study can serve as a reference for the use of gabion walls in the development of practical building designs.