This Article provides the first legal examination of the immensely valuable but underappreciated phenomenon of social innovation. Innovations such as cognitive behavioral therapy, microfinance, and strategies to reduce hospital-based infections greatly enhance social welfare yet operate completely outside of the patent system, the primary legal mechanism for promoting innovation. This Article draws on empirical studies to elucidate this significant kind of innovation and explore its divergence from the classic model of technological innovation championed by the patent system. In so doing, it illustrates how patent law exhibits a rather crabbed, particularistic conception of innovation. Among other characteristics, innovation in the patent context is individualistic, arises from a discrete origin and history, and prioritizes novelty. Much social innovation, however, arises from communities rather than individual inventors, evolves from multiple histories, and entails expanding that which already exists from one context to another. These attributes, moreover, apply in large part to technological innovation as well, thus revealing how patent law relies upon and reinforces a rather distorted view of the innovative processes it seeks to promote. Moving from the descriptive to the prescriptive, this Article cautions against extending exclusive rights to social innovations and suggests several nonpatent mechanisms for accelerating this valuable activity. Finally, it examines the theoretical implications of social innovation for patent law, thus helping to contribute to a more holistic framework for innovation law and policy.