Abstract: A chair-borne musical instrument support that is both adjustable and portable. The musical instrument support includes a seat portion having an adjustably attached support arm with an instrument rest attached to the top thereof. The musician places the seat portion of the device on the seat of a chair, and then sits on the seat portion. The support arm and instrument rest extend upward near the front edge of the chair and between the legs of the musician. The weight of the musician sitting on the chair holds the device in place. Alternatively, the musical instrument support may be held in place on a chair by adjustable straps. The base of the tuba is then placed upon the instrument rest which is covered with a non-abrasive, non-skid surface. The support arm and instrument rest may be adjusted vertically up or down to a comfortable height. The instrument then rests in the same position as if it were being held on the musician's lap, but now it does not have to be borne by the musician's legs.