Abstract: A sleeping compartment (10) for a truck is made up of a plurality of pre-assembled sections or modules including a first type (14, 14?, 14?) having one or more seats and a second type (16, 86, 86? , 86?) having a bed. In accordance with one aspect of the invention, a seat (60) is mounted on a sidewall (22, 22?, 22?) of the first type of module and includes a seat bottom (66) moveable from a substantially vertical stowed position against the side wall and a substantially horizontal deployed position. A seat support (34) mounted on the floor (20) is movable from a stowed position substantially flush with the floor of the first type of module to a deployed position protruding upwardly from the floor to support the seat bottom in the deployed position. The seat support is preferably a door panel covering a storage space (32) beneath the floor which is accessible from outside the sleeping compartment.