A space-dividing wall panel system (10) having a plurality of upright wall panels (12) serially connected one with the other by an intermediate upright support post (22). The height of each wall panel (12) is adjusted by modular panel extension assemblies (16) which are mounted on base panels (14) supported by lower support posts (23) and include extension posts (24) connected to the lower supports posts (23) so as to be arranged coaxially therewith.
