Resin-impregnated sandwich composite backpack frames are disclosed. The frames may, for example, be made of a carbon fiber twill with a foam core. The frames have an upper portion that includes upwardly-extending, elongate stays to support a backpack and mechanically decouple its load from the wearer. Open, generally vertically extending tracks in the upper portion provide points of attachment for shoulder strap assemblies. The lower portion is contoured to follow the typical lumbar-sacral curvature of the human back and terminates in a generally U-shaped tongue. Openings and unreinforced areas in the frame are provided to reduce weight and increase flexibility.