The invention relates to an electrohydraulic actuator comprising a hydraulic piston, a spindle drive for moving the piston along an axis of rotation, wherein the spindle drive comprises a spindle and a nut, and a worm wheel, which is coaxially attached to the nut. Furthermore, an electric motor having a worm, which meshes with the worm wheel, is provided. The nut is radially and axially supported by means of a bearing. In addition, there is a single-armed rotation-prevention mechanism in order to prevent the spindle from rotating. An angle with respect to the axis of rotation is included between a point of action of the worm on the worm wheel and the effective direction of the rotation-prevention mechanism, wherein the angle is selected in such a way that, for a predetermined torque acting on the nut, a radial force acting on the piston is minimized.