A folding hood for motor vehicles has a hood frame supporting the hood cover and being fordable to an open position in order to stretch the hood cover, and a reinforcement of the stretched hood cover, adjoining a strut supporting the cover, by way of a shaping shell mounted between the strut and the hood cover. Because of its dimensional rigidity, the cover interacts in a shaping manner with the hood cover resting flat thereon. The shaping shell is positioned under the hood cover via a tensile connecting device extending transversely to the strut and stretched tightly when the hood frame is folded open. In order to permit a space-saving storage position of the folding hood even with a larger-sized shaping shell the shaping shell is transversely deformable, in a flexurally resilient manner, about a longitudinal axis extending along its bearing position on the strut. When the folding hood is open, the shaping is retained in a relaxed initial position. The shaping shell can only be bent into its shaping position of use by way of the tensioning advance of the tensile connecting devices when the folding hood is closed.