A posture support system, which may alternatively act as a structural support for a backpack and/or be incorporated in a body garment or undergarment, employs a pair of contoured cap sleeves which cradle the humeral heads so as to extend over the scapulas and down over the humerus. The forward end extends as a strap under one of the armpits and connects at its end to the top of a vertically extending central strap extending over the spine. The central strap connects to a waist encircling lumbar support strap. The posterior strap-like ends of the shoulder caps extend over the back and also connect to the top of the spinal strap. By use of adjustable connections to a central disk at the top of the back strap and elastic fabrics in the straps, the shoulders are pulled rearwardly and downwardly so that the body weight is supported over the hips.