A reversible-lid arrangement for a motor vehicle includes a floor panel having an opening, a lid member, and a pair of oppositely-arranged guide rails. The lid member is so sized as to close the opening, and has first and second side surfaces which are opposed to each other. The lid member has first and second projections which are formed on the first side surface and spaced away from each other with a certain predetermined distance therebetween, and third and fourth projections which are formed on the second side surface and spaced away from each other with the predetermined distance therebetween. The guide rails are so sized and spaced away from each other as to fit therein the first, second, third and fourth projections of the lid member. Each guide rail has first and second notches each of which is so sized as to allow one of the first, second, third and fourth projections to pass therethrough, and so positioned as to expose the one of the first, second, third and fourth projections when the opening of the floor panel is fully closed by the lid member. Thus, the lid member can be easily and quickly turned upside down without requiring much space.