This paper draws on the model of technology appropriation (MTA) in order to assist in understanding the integration of systems in a Defence context. The MTA describes the process of appropriation through which technology is adopted, adapted and integrated with work practices. As users appropriate a technology they are completing the design process. The contribution of this paper is the application of a model that provides a lens for understanding the process through which the design of a technology is completed by humans embedded in a particular organisational context, and which provides insights into how to improve design practices associated with systems integration.