Abstract: A support harness for a child who, due to brain damage or disease, lacks trunk or head control sufficient to achieve or maintain a normal sitting position, said support harness being characterized in that it comprises two layers of a fabric which combines firmness and softness and which is of shape to define a back portion with upper and lower strap means for fastening the harness to the backrest of a chair; laterally extending side flaps (with foam rubber or like padding therein) adapted to be wrapped over the sides of the child's body between the armpits and the hips and across the chest and abdomen and secured together in overlapping relation by releasable fastening means; a longitudinal flap from the lower end of the back portion which is of progressively narrowing width to pass through the child's crotch and upwardly over the overlapped lateral flaps; and shoulder straps for releasably interconnecting the upper ends of said longitudinal flap and back portion.