Abstract: A foundation system made up of panels for supporting a load bearing surface on underlying ground in use. Each foundation panel has a panel body having a peripheral edge, first and second opposing major surfaces spaced by a depth dimension of the panel body, and a plurality of internal walls upstanding in the depth dimension so as to define a plurality of cells within the panel. Each cell of the panel is open at one of the first and second major surface and closed at the other of the first and second major surfaces. Connection formations are provided at the peripheral edge of the panel body, where the connection formations comprise a neck portion and a head portion. The head portion is configured to engage with a corresponding connection formation of one or more adjacent panel in use to resist separation of the foundation panel from an adjacent panel in a direction within a plane of the first or second major surface.