The finite element computations were performed on ABAQUS/Explicit solver to study the effect of wall thickness on axial crushing and energy absorption of the mild steel tubes under axial impact. Circular tube (60 mm diameter) and square tube (47.34 mm size) with varying wall thicknesses (1.1, 1.5, 2, 2.5, and 3 mm) were impacted axially by 5 kg projectile. A comparative study has also been carried out on axial compression behavior of tubes with circular and square tubes with equivalent section areas. The constitutive and damage behavior of the mild steel was modelled using the Johnson-Cook material model. The validation of the computational model was carried out by performing the experiments on 60 mm diameter circular tube under the axial impact of 5 kg projectile. The maximum axial compression of the circular and square tubes has been found to be decreased with an increase in the wall thickness of the tubes, however, the absorbed energy does not show any significant influence with the change in the wall thickness of the tubes. The maximum axial compression of the square tubes was found to be higher than the circular tubes for thicknesses 1.1 and 1.5 mm. On the other hand, the axial compression of the circular tubes was found higher at higher thicknesses beyond 1.5 mm.