Model management emerged in the mid-seventies in the context of managing models in decision support systems (DSS). With the recent advances in computer and telecommunication technologies, organizations are ever increasingly dependent on management models for data analysis and decision support. Accordingly, the number and complexity of management models and of modeling platforms dramatically increased rendering such models a corporate (and national) resource. With the advent of the Web and distributed computing environments, there is also an increasing demand to share these often heterogeneous models over corporate intranets as well as the Web. To this end, this paper presents an XML-based architecture for sharing heterogeneous models in Web and distributed computing environments. The architecture includes an XML schema for representing models. The schema is based on the structured modeling paradigm as a formal mathematical environment for conceiving, representing and manipulating a wide variety of models. The architecture allows different types of models, developed in a variety of modeling platform to be represented in a standardized format and shared over the Web. The paper demonstrates the proposed architecture through a case study.