The chapter begins by explaining a framework, maturity model and standards for interoperability. In the latter part of the chapter, after introducing the concept of model driven architecture (MDA), it describes aspects of model-driven interoperability (MDI). Interoperability is the ability of interaction between two or more systems so as to achieve some goal without having to know the uniqueness of the interacting systems. Interoperability involves business applications on distributed platforms tied together in a number of different ways, such as by transaction monitors, message-oriented middleware, data access middleware, Web services, and remote procedure calls (RPCs), or sometimes by clumsier mechanisms like file transfers or sequential batch processing jobs. This chapter’s appendix describes aspects related to the integration of applications. It describes the basics and models of integration including presentation, functional, data, business process, and business-to-business integration. The last part of the chapter explains the various patterns of integration.