This chapter describes the history of the term social innovation as part of a discontinuous conceptual discussion with solid references to the debate about a socio-theoretically based understanding of social change and societal transformation. It identifies individual research fields in which the term has been increasingly used in recent years. The focus here is particularly on research into regional and local development as well as social entrepreneurship research. With the growing importance of the concept in societal and political debate, an intensification of scientific engagement with the topic can be observed. The debate is receiving new impetus from research into sustainable development and social practice theory. In this process, the contours of a new overarching research field are becoming visible. For further development of the research, this results in both thematic expansions, particularly with regard to the investigation of power relations, and the need for a socio-theoretical foundation of the field.