Background: We are witnessing increasing demand from governments and society for all sciences to have relevant social impact and to show the returns they provide to society. Aims and objectives: This paper reports strategies that promote social impact by Social Sciences and Humanities (SSH) research projects. Methods: An in-depth analysis of six Social Sciences and Humanities research projects that achieved social impact was carried out to identify those strategies. For each case study, project documents were analysed and qualitative fieldwork was conducted with diverse agents, including researchers, stakeholders and end-users, with a communicative orientation. Findings: The strategies that were identified as contributing to achieving social impact include a clear focus of the project on social impact and the definition of an active strategy for achieving it; a meaningful involvement of stakeholders and end-users throughout the project lifespan, including local organisations, underprivileged end-users, and policy makers who not only are recipients of knowledge generated by the research projects but participate in the co-creation of knowledge; coordination between projects' and stakeholders' activities; and dissemination activities that show useful evidence and are oriented toward creating space for public deliberation with a diverse public. Discussion and conclusions: The strategies identified can enhance the social impact of Social Sciences and Humanities research. Furthermore, gathering related data, such as collaboration with stakeholders, use of projects' findings and the effects of their implementation, could allow researchers to track the social impact of the projects and enhance the evaluation of research impact.