Transport system for a wind turbine rotor blade, comprising a wind turbine rotor blade, a front bearing device to which a blade root side end of the wind turbine rotor blade is fixed, the front bearing device being adapted to support the wind turbine rotor blade on a tractor unit, a powerless trailing vehicle having a rear bearing device to which a rear, blade tip side portion of the wind turbine rotor blade is secured, and a stiffening device for the wind turbine rotor blade comprising a first coupling device, a second coupling device and a connecting means, wherein the first coupling device is fixedly connected to the wind turbine rotor blade relative to the longitudinal axis of the wind turbine rotor blade in a forward, blade root side region of the wind turbine rotor blade, the second coupling device is fixedly connected to the wind turbine rotor blade in the rear portion of the wind turbine rotor blade with respect to the longitudinal axis of the wind turbine rotor blade, characterized in that the two coupling devices (156, 158) are braced together by means of the connecting means such that the connecting means is loaded in tension and the two coupling devices (156, 158) are pulled together or held together against a deflection force generated by the rotor blade, so that the stiffening device together with the wind turbine rotor blade forms a self-supporting or cantilevered stiffening structure, thereby counteracting deflection of the wind turbine rotor blade between the two coupling devices (156, 158). a front bearing device to which a blade root side end of the wind turbine rotor blade is fixed, the front bearing device being adapted to support the wind turbine rotor blade on a tractor unit, a powerless trailing vehicle having a rear bearing device to which a rear, blade tip side portion of the wind turbine rotor blade is secured, and a stiffening device for the wind turbine rotor blade comprising a first coupling device, a second coupling device and a connecting means, wherein the first coupling device is fixedly connected to the wind turbine rotor blade relative to the longitudinal axis of the wind turbine rotor blade in a forward, blade root side region of the wind turbine rotor blade, the second coupling device is fixedly connected to the wind turbine rotor blade in the rear portion of the wind turbine rotor blade with respect to the longitudinal axis of the wind turbine rotor blade, characterized in that the two coupling devices (156, 158) are braced together by means of the connecting means such that the connecting means is loaded in tension and the two coupling devices (156, 158) are pulled together or held together against a deflection force generated by the rotor blade, so that the stiffening device together with the wind turbine rotor blade forms a self-supporting or cantilevered stiffening structure, thereby counteracting deflection of the wind turbine rotor blade between the two coupling devices (156, 158). the first coupling device is fixedly connected to the wind turbine rotor blade relative to the longitudinal axis of the wind turbine rotor blade in a forward, blade root side region of the wind turbine rotor blade, the second coupling device is fixedly connected to the wind turbine rotor blade in the rear portion of the wind turbine rotor blade with respect to the longitudinal axis of the wind turbine rotor blade, characterized in that the two coupling devices (156, 158) are braced together by means of the connecting means such that the connecting means is loaded in tension and the two coupling devices (156, 158) are pulled together or held together against a deflection force generated by the rotor blade, so that the stiffening device together with the wind turbine rotor blade forms a self-supporting or cantilevered stiffening structure, thereby counteracting deflection of the wind turbine rotor blade between the two coupling devices (156, 158).