Method for assisting a driver of a motor vehicle with a hitched trailer when parking the motor vehicle with the trailer in a parking space with the aid of a driver assistance device of the motor vehicle , having the steps of: a) determining at least an overall dimension of the motor vehicle with the hitched trailer in dependence on at least one specified dimension of the trailer by way of a computation device of the driver assistance device ; b) capturing environment data relating to a parking space in an environment of the motor vehicle by way of a sensor device of the driver assistance device ; c) parking the motor vehicle with the hitched trailer in the parking space , wherein c1) during the parking operation, the parking space is located at least in part outside a current capturing region of the sensor device of the motor vehicle ; c2) at least one distance (d a , d b , d c ) from the trailer to a boundary of the parking space is ascertained by way of the computation device in dependence on a position of the motor vehicle relative to the parking space and the overall dimension of the motor vehicle with the hitched trailer ; and c3) if the ascertained distance (d a , d b , d c ) is less than a specified minimum distance (d min ) , an alert is issued to the driver by way of the driver assistance device , characterized in that the determination of the overall dimension during the parking operation according to step c) is continuous and the overall dimension is determined in dependence on a hitching angle (α) of the trailer . a) determining at least an overall dimension of the motor vehicle with the hitched trailer in dependence on at least one specified dimension of the trailer by way of a computation device of the driver assistance device ; b) capturing environment data relating to a parking space in an environment of the motor vehicle by way of a sensor device of the driver assistance device ; c) parking the motor vehicle with the hitched trailer in the parking space , wherein c1) during the parking operation, the parking space is located at least in part outside a current capturing region of the sensor device of the motor vehicle ; c2) at least one distance (d a , d b , d c ) from the trailer to a boundary of the parking space is ascertained by way of the computation device in dependence on a position of the motor vehicle relative to the parking space and the overall dimension of the motor vehicle with the hitched trailer ; and c3) if the ascertained distance (d a , d b , d c ) is less than a specified minimum distance (d min ) , an alert is issued to the driver by way of the driver assistance device , characterized in that the determination of the overall dimension during the parking operation according to step c) is continuous and the overall dimension is determined in dependence on a hitching angle (α) of the trailer . c1) during the parking operation, the parking space is located at least in part outside a current capturing region of the sensor device of the motor vehicle ; c2) at least one distance (d a , d b , d c ) from the trailer to a boundary of the parking space is ascertained by way of the computation device in dependence on a position of the motor vehicle relative to the parking space and the overall dimension of the motor vehicle with the hitched trailer ; and c3) if the ascertained distance (d a , d b , d c ) is less than a specified minimum distance (d min ) , an alert is issued to the driver by way of the driver assistance device , characterized in that the determination of the overall dimension during the parking operation according to step c) is continuous and the overall dimension is determined in dependence on a hitching angle (α) of the trailer . <EOS>