A device for detecting a pendulum motion of a vehicle. The device includes at least one first ascertainment arrangement, with which a lateral-motion-dynamics quantity is ascertained that represents the lateral motion dynamics of the vehicle. In addition, the device includes a second ascertainment arrangement with which a speed quantity is ascertained that describes the vehicular speed. With the aid of a third ascertainment arrangement it is ascertained, as a function of the at least one lateral-motion-dynamics quantity and the speed quantity, whether a pendulum motion of the vehicle exists. For that purpose, it is at least checked whether the at least one lateral-motion-dynamics quantity is greater than an associated threshold value and the speed quantity is greater than an associated threshold value. A pendulum motion of the vehicle exists when the lateral-motion-dynamics quantity is greater than the associated threshold value and when the speed quantity is greater than the associated threshold value.