This learning brief has been informed by an in-depth review of the program documentation and interviews with The SEEP Network, the Association of Microfinance Institutions Rwanda (AMIR), and other program stakeholders within and outside of Rwanda. This learning brief starts with an introduction to a Market Systems Development (MSD) approach and showcases the core considerations that need to be taken when designing this approach. It then explains how this was applied in the RFL3 context. This is followed by a discussion of the successes and challenges faced in implementing this approach through the RFL3 program. The learning brief concludes by extracting the lessons from the RFL3 program that are relevant to other programs implementing an MSD approach.