In this paper we investigate various aspects of representing multidimensional information in the frame of the WWW. Multidimensional XML (MXML) is an extension of XML suitable for representing data that assume di erent facets, having di erent value or di erent structure, under di erent contexts. In Multidimensional XML, elements and attributes may depend on a number of dimensions, that de ne worlds under which variants of those elements or attributes hold. Moreover, we propose an extension of DTD that takes dimensions into account and is suitable for describing the logical structure of MXML documents. We also present a graph data model for MXML, and show how MXML can be reduced to conventional XML for a given world.