Abstract: An adjustable drapery support assembly comprises a vertical elongated base which can be attached at its lower end to the rear surface of a drapery at a point opposite a preformed pleat therein, with the upper end of the base adjacent the upper edge of the drapery. The base is provided at its upper end with a hinged clamping arm which engages the upper edge of the drapery, thereby inhibiting outward sagging of the top thereof. In a preferred embodiment, the clamping arm is provided with a plate member of limited vertical dimension adapted to enter the open end of the pleat, thereby maintaining the angular orientation thereof. The support assembly includes an adjustable hook assembly which can be attached at any desired point along the length of the base.