The inelastic scattering dynamics of N2 off W(001) has recently been the subject of theoretical investigations, which were found to be unable to describe low-collision-energy molecular beam experiments. This discrepancy was suggested to originate from the neglect of van der Waals interactions in the construction of the potential energy surface. By making use of a newly developed potential energy surface, accounting for such dispersion interactions, we show that quasi-classical dynamics simulations, including dissipation to surface electrons and phonons, lead to an adequate description of the low-collision-energy experiments and, more specifically, the trapping-desorption component of inelastic scattering. This work highlights the prominent influence of van der Waals forces on gas–surface dynamics observables in the low-collision-energy regime.