An interlock connector interlocks building blocks that are assembled so as to provide a wall structure. The building blocks have respective front surfaces for defining a front façade of the wall structure and respective rear surfaces with at least one respective horizontal groove. The interlock connector comprises first and second bodies. The first body is inserted in the rear surface horizontal groove of a first building block. The second body is inserted in the rear surface horizontal groove of a second building block adjacent the first building block. Insertion of the first and second bodies in the respective rear surface horizontal grooves of the first and second building blocks provides for interlocking the first and second building blocks.