A modular furniture unit includes vertical panel members which are fixed to a horizontally planar base panel and a horizontally planar top panel. In a first embodiment two coplanar vertical panel members are fixed to a vertical support panel by pins received through the support panel, and the horizontal panels are fixed to the vertical panels by bolts which are secured by rotatable cams in the vertical panels. In a second embodiment two vertical panel members are provided with interengaging vertical slots so that they can be fitted together at right angles without any support panel.