Abstract: A top cap arrangement for an interior space-dividing wall panel arrangement which mounts on and projects upwardly from a floor for dividing a floor area into a plurality of smaller working areas. The panel arrangement is defined by a plurality of individual panel members which are less than ceiling height, and have an interior frame construction which includes an elongate top frame element which extends along and defines the upper surface of the panel member. A top cap member mounts on and extends horizontally along the top frame element, and is constructed of a material which permits at least limited transverse flexibility. The top cap member has a channel-like configuration which includes outer side flanges which slidably overlap and embrace exterior sides of the panel member to permit at least limited vertical positional adjustability of the top cap member relative to the panel member.