Ground vehicles often encounter turbulent flows with wide range of scales, e.g. crosswind gusts, when moving on-road conditions. Crosswinds can be considered as an important factor in heavy vehicle’s roll-over accident due to their relatively high center of gravity and lateral surface area. However, there are few studies which investigate effects of crosswinds on heavy vehicles. Furthermore, existing studies have generally focused on lateral or yaw dynamics of heavy vehicles and neglected their roll dynamics. Therefore, effects of crosswinds on heavy ground vehicles should be understood in all aspects in order to design less wind-sensitive vehicles especially at early stages of their design processes. Inherently, crosswind studies require a multidisciplinary approach which involves coupling between aerodynamics and vehicle dynamics. In the present study, investigation of effects of the coupling methods, e.g. one-way and two-way couplings, between aerodynamics and vehicle dynamics simulations are aimed by considering both lateral and roll dynamics of heavy vehicles which are subjected to crosswind gust. Vehicle dynamics and aerodynamics results are presented. Results of the one-way coupled simulations, in general, overestimate the absolute maximum values of the vehicle dynamics results. However, differences in lateral displacement results Δymax are less than 0.2 m for the studied case.