Abstract: A guitar neck is formed with a protruding trapezoidal heel which extends into a pocket formed at the neck end of the body. The tendency of the strings to bend the neck is counteracted by a truss rod assembly which is positioned in a contoured channel formed in the neck beneath the fingerboard. The assembly has a threaded stainless steel rod which extends through an aluminum U-channel, with one end extending beyond the U-channel beneath and adjacent the first fret of the fingerboard, where it is fixed to the U-channel, and the other end extending out of the U-channel adjacent the neck-body joint, where an adjustable hex nut is threaded on the rod which bears on a washer. Two cylindrical spacers are fixed to the rod within the U-channel at positions upward of the neck joint which serve to hold the rod in the center of the U-channel between the U-channel legs, and also spaced outwardly from the base of the U-channel to thereby cause the rod to bow away from the base into the contoured channel in the neck.