A shoulder belt positioner is provided for vehicles, and the like of the type having safety belt restraint systems. The positioner comprises a flexible strap having a hanger bracket at one end, and an open hook at the other end. The hanger bracket releasably supports the positioner on the door of the vehicle, preferably by an inverted U-shaped clip that is closely received in the window slot of the vehicle door. The positioner hook has a generally V-shaped configuration to releasably engage the shoulder belt in the extended, locked position, and pull the same slightly off of the user's shoulder to provide improved comfort. The positioner hook automatically releases the shoulder belt when the belt is moved to its retracted, storage position. The positioner preferably moves with the door as it is opened to an out of the way location to permit unobstructed exit from and entry into the vehicle.