Behavioural design has emerged as a critical new area of research and practice. However, despite the development of extensive lists of possible problem features and suggested solution principles there is little guidance on how these should be connected. Therefore, in this work we systematically examine interactions between major problem features and solution principles, based on an analysis of 218 behavioural design interventions drawn from 139 cases across design domains and foci. This forms the basis for a number of contributions. First, we bring together behavioural and designerly perspectives on problem characterisation via two proposed problem features: change
demand and behavioural constraint, related in a two-by-two framework. Second, we synthesised recommendations from across domains and foci to operationalise a list of 23 solution principles relevant to designers. Third, we link these insights in a proposed Behavioural
Problem/Solution (BPS) matrix. Further, we identify a number of potential systemic challenges in the reporting and evidencing of behavioural design interventions. Together, these insights substantially extend both theory and practice surrounding problem-solution mapping in behavioural design, and form a foundation for further theory development and synthesis in this area.