The paper investigates the influence of changing the stiffness of anti-roll bars on the dynamic behavior of a vehicle. Considering the anti-roll bar with a linear elastic behavior, the stiffness calculation relations for a common anti-roll bar shape are presented. The 7-degree-of-freedom (DOF) model presented was obtained taking into account the displacements of the unsprung and sprung masses, the roll and pitch angles. The forces due to the unequal displacements that occur on the same axle due to the action of the anti-roll bar were added to the existing dynamic forces. The expressions of the inertia, viscous damping and stiffness matrices are presented. The example illustrated presents the results obtained in the case of anti-roll bars with mobile supports. These are presented in the form of diagrams and tables. The model can also be used in the case of active anti-roll bars operated by motor mechanisms or braking systems.