An obvious quest for system development researchers is to understand, describe and give advices concerning the domain of system development. One part of this domain is the System Development Practice (SDP). SDP means the way that system development projects are planned, structured and carried out in order to produce a product that creates value for its client. Our experiences are that SDP often involves three major dimensions; action pattern, method, and role interaction. In these three structural views we find concepts and aspects that are of importance such as, system life cycle, model, method, results, resources, milestones, project roles, project group constellations, clients etc. These dimensions with their concepts and aspects make the SDP a complex phenomenon to its character. In this paper we will therefore give a character to each of these three dimensions and how these dimensions can constitute the SDP as a whole, i.e. a conceptualisation of the SDP. To accomplish this goal we have based this paper on three major sources for inspiration and generation of knowledge within the problem domain that we have identified. Firstly, we all have experiences from several projects and work where we during recent years in different ways have taken part in projects where development of SDP has been in focus. Secondly, empirical experiences from several projects where development of the SDP has been in focus, and thirdly, theories related to the SDP domain. The approach bears on the foundation of language action theories for information systems, information system development and practices for understanding the domain of SDP. By identifying essential acts performed in SDP’s we are able to regard the relations between the three dimensions in order to form a holistic view, which means that we can understand and have constructive discussions about SDP’s.