Social innovations are urgently needed as we confront complex social problems. As these social problems feature substantial interdependencies among multiple systems and actors, developing and implementing innovative solutions involve the re-negotiating of settled institutions or the building of new ones. In this introductory article, we introduce a stylized three-cycle model highlighting the institutional nature of social innovation efforts. The model conceptualizes social innovation processes as the product of agentic, relational, and situated dynamics in three interrelated cycles that operate at the micro, meso, and macro levels of analysis. The five papers included in this special issue address one or more of these cycles. We draw on these papers and the model to stimulate and offer guidance to future conversations on social innovations from an institutional theory perspective.