Abstract: A modular building system comprising one or more wall panels having a top edge defining one of a male or female configuration and a bottom edge defining the other one of a male or female configuration such that the top edge of one wall panel can mate with the bottom edge of an upper wall panel. The wall panels also have a first side edge defining one of a male or female triangular interlock and a second side edge defining the other one of a male or female triangular interlock such that the first side edge of one wall panel can interlock with the second side edge of another wall panel. Additionally, the wall panels have a clip extending from one wall panel to another to secure the first side edge of the one wall panel in position with the second side edge of another wall panel.