Organisations that wish to establish IT-supported business relationships with business partners face major challenges, among them the need for creating a win-win-situation and the effort to align business processes and link up information systems across company borders. Whereas interoperability has been widely discussed in a technical context, it has not (yet) been explored how interoperability relates to the business strategy and organisational design of the business relationship. This paper explores interoperability from a business perspective and identifies the fundamental artefacts related to business interoperability. Building on contingency theory, it outlines a comprehensive framework suggesting a fit between the level of business interoperability and environmental as well as internal contingencies.