Social innovation provides innovative solutions to address healthcare delivery challenges, but it relies on engaging communities and various health system actors to be effective. The Social Innovation in Health Initiative (SIHI) previously collected detailed information on 40 innovation projects from around the world, through case study research. This contributed to scientific evidence, stakeholder awareness and utilization of social innovation in health programs. However, there is limited information on contextual factors that influence community engagement in social innovation and health research. The purpose of this study was to understand the extent of community engagement and the contextual factors affecting engagement of communities in social innovation and health research. A sequential mixed-methods study design was employed from 2021-2022. First, we conducted qualitative secondary analysis of the existing 40 social innovation case studies. We identified themes and extracted relevant data to community engagement and other characteristics from the case studies. Additionally, we conducted 27 qualitative interviews with the innovators of the same social innovations projects identified by the SIHI network. Interviews were held online using zoom, audio recorded, transcribed verbatim and imported in N-Vivo 11 for thematic analysis. Using the NIH community engagement framework, we determined community engagement in social innovation as being either informative, consultative, involving, or collaborate and shared leadership. Themes identified from the case studies and key informant interviews informed the development of an online quantitative survey questionnaire on community engagement in social innovation. The survey was completed by a total of 275 participants from around the world. Across the different methods of data collection, community engagement was found to be very strong in the social innovation projects. The majority (about 75%) exhibited collaboration and shared leadership with communities during the design, implementation and evaluation of the activities. The advantages and motivation for community engagement included empowerment of beneficiaries, improving quality of the interventions and their utilization and ownership. Weak community engagement was shown to lead to less participation and ownership. In conclusion, community engagement was found to be strong in the social innovation project was necessary for sustainability and local ownership of projects.