In this chapter the authors explore the emergent literature on social innovation and make ties to the affective underpinnings of these activities. Referencing a typology of social innovation developed by Tracey and Stott in 2017 outlining three major types of social innovation – social entrepreneurship, social intrapreneurship and social extrapreneurship – the authors draw on three metaphors to examine the role of emotions in social innovation: emotions as fuel, emotions as glue and emotions as rust. They develop the metaphors theoretically, reviewing relevant literature on social innovation, and then use the metaphors to derive a research agenda for each type of social innovation. The authors conclude the chapter with a call for future work in this important domain of scholarship.