Reverse Logistics (RL) of end-of-use/end-of-life products is a key approach for supporting the transition to a circular economy. However, lack of knowledge and experience in designing RL is one of the barriers for companies in implementing successful RL. This research proposes an RL support tool (RLST) for designing RL systems, developed through iterative cycles of theoretical development and empirical testing/feedback from potential users. The RLST builds upon the principles of configuration systems to adapt the various aspects of RL design into a knowledge base and, subsequently, into an Excel-based support tool - in addition to allowing companies to assess their motivation/driver and set the context (e.g., product characteristics, the existence and nature of Extended Producer Responsibility (EPR) legislation), it supports the design of the RL network/channel and other aspects such as stakeholder collaboration, legislation, consumer behaviour and incentives, use of digital technologies, key performance indicators and factors around governance/programme management. Such a tool can be helpful for practitioners in addressing the knowledge gaps, stimulating discussions among stakeholders for scenario building and for analysing how different scenarios might work. The research advances the knowledge on RL systems design for the circular economy along with, for the first time, building knowledge and application of configuration systems in the field of RL.