A building module has an exterior shape generally of a cuboid having side, end, top and bottom faces, and fabricated from metal, the module being hollow and defining a space of a size suitable for occupation by a person. The module includes fastening elements (21, 69) to allow the module to be fastened to another adjacent module and to allow for engagement by standard load handling equipment for handling freight containers. The module has an overall exterior width greater than 2700 mm and includes a first set of fastening elements (21, 69A, 69B, 69C, 69D) in the region of a first end of the top of the module and a second end of the top of the module. The fastening elements of each set include two fastening elements (e.g. 21 and 69C) spaced apart from one another at a centre-to-centre spacing (D) of about (2260) mm.