Based on the assumption that agricultural development increasingly involves complex undertakings, a consensus is now acknowledged regarding crucial priority to promote innovations within agriculture and across food systems in the Global southern countries (including Africa) aiming at realizing economic growth and inclusive development. Such innovations can be enhanced by a broad range of innovation support services (ISS) presently provided by a pluralistic field of support service providers (ISP). Nevertheless, the broad picture shows a multitude of suppliers addressing innovative initiatives with various approaches, tools, funding and governance mechanisms as well as varied visions of sustainability and development particularly in African context where international organization and agencies are involved into the promotion of innovations. This paper presents a system-oriented conceptual framework co-designed within the LEAP-AGRI SERVInnov project to characterize and assess ISS and ISP in three African countries: Burkina, Cameroun and Madagascar. The main finding is the need to adapt the Agricultural Innovation System AIS) approach through the involvement of hybrid and informal actors. Another insight focuses on the need to consider the ISS agricultural sub-systems that encompasses the co-existence of a pluralistic vision of sustainable development (including funding mechanisms) and, what transpires during a service relation situation. These findings should help, firstly ISPs to better design their interventions in order to reinforce their supporting activities toward innovations and secondly, help decision makers to better manage the innovation support services at the system level. The main scientific input is the development of the concept of innovation support system deduced from AIS.