Most current information system s (IS) planning methodologies are focused on achieving ‘successful’ plans, i.e. plans that provide competitive advantage, can be implemented in a given period of time, and that solve the problems of information needs by taking advantage of the latest technologies available. Concerns are technology and business driven, and focus on how to get the maximum profit for organisations from investing in information systems. However, this relatively narrow focus can be problematic, especially in developing countries where the social contexts of IS implementation may require a different primary focus. This chapter presents a methodology for IS planning based on critical systems thinking – an approach that encourages the critical analysis of stake holder understandings of social contexts prior to the selection and/ or design of planning methods. The methodology presented in this chapter uses a combination of the systems theories of autopoiesis and boundary critiques, which deepen our understanding of what it means to reflect on participation, values and social concerns during IS planning. In the course of applying the methodology in a project in Colombia, an issue arose of the ethics of the practitioner. To address this issue, following completion of the project, we sought to enhance critical systems thinking with Foucault ’s notions of power and ethics, which offer interesting alternatives for practitioner self-reflection. Implications for IS planning are derived from this perspective on ethics and power.