Global service-learning brings students, instructors, and communities together to support learning and community development across borders. In global service-learning, practitioners act at the intersection of two fields: service-learning and international development. Critical scholarship in all service-learning and international development has highlighted the tensions inherent in defining and tracking “success” in community development. In response, service-learning and international development have turned considerable attention to documenting project characteristics, also known as best practices or success factors, that support equitable, sustainable community development. This article presents a systematic synthesis of these fields’ best practices in the context of global service-learning. The authors propose 18 guiding principles for project design to support practitioners in creating and maintaining justice-oriented, stakeholder-driven projects. The authors compare these principles to emerging best practices in global service-learning and assess the contribution of service-learning and international development research to informing the future of the field.