The aim of this paper is to show how speech act theory can be used in systems development as a theoretical foundation for conceptual modelling. With the traditional notion of the conceptual model as an image of reality, the predominant modelling problem is to analyse how the external reality should be mapped into, and represented in, the system in a ‘true’ way. In contrast to this, we maintain that the main modelling problem should be to analyse the communication acts performed by use of the system within its business context. This implies an integration of traditional conceptual modelling with action-oriented business modelling based on speech act theory. With such an approach it is possible to reconcile traditional conceptual modelling and the pragmatic aspects of language and computer use. It is argued that such reconciliation is essential to arrive at systems that provide relevant information to users and in which users can trace responsibilities for information, actions and commitments made.