Systems engineers have often paid too little attention to the nature of the so-called “users” of products under development. These are better called Stakeholders, as many roles are involved, and few of those are in direct contact with the developed products. A simple and robust conceptual framework for classifying development stakeholders – a taxonomy – is proposed. The taxonomy is product-centric, with concentric ‘Circles’ denoting broad categories of stakeholder. Within these, generic ‘Slots’ describe typical classes of stakeholder; these are subdivided into ‘Roles’ which are expected to vary at least in name with the domain. Examples are given, and a popular template is reanalysed using the framework. The taxonomy has immediate value in identifying and validating stakeholder roles in requirements elicitation. This helps to ensure that key viewpoints on requirements are not missed. That in turn reduces the risk of instability and failure during development.