Abstract: A harness and shoulder strap assembly to securely enclose, support, and form a carrying device for musical instrument cases. The case-engaging harness and shoulder straps are comprised of a plurality of adjustable strap loops connected by various fastenings, adjusters, releasable buckles, joiners, and fixing methods. The harness and shoulder strap assembly can safely support and carry a wide variety of size, shape, and style instruments and instrument cases.