Abstract: A modular construction system for connecting two or more structural members, comprising a universal unit for connection to a first structural member, the unit having at least one planar surface adapted to be oriented in substantially vertical orientation, one or more posts projecting in substantially horizontal orientation from the planar surface, and a pair of finger members defining vertical channels on opposite sides of the one or more posts. One or more connector units are also provided for removable connection to the universal unit, each of the connector units having a planar flange member adapted to be received in the vertical channels and to rest on the one or more posts, and one or more tongue members connected to the flange unit for receiving one or more additional structural members.