Despite the comprehensive previous research on different aspects of inventions and externalities spanning both the micro- and macrolevels, no prior studies have, to our knowledge, examined the relationship between the commercialization strategies of inventions/patents and social knowledge spillovers. To bridge this gap in the literature, we examine how such spillovers, measured as forward citations, covary with four commercialization modes: (1) setting up a new firm, (2) commercialization within an existing firm where the inventor either is employed or (3) has an ownership stake, and (4) licensing/selling patents to other firms. Alternatively, an inventor may refrain from commercialization. Utilizing unique survey data on patents owned by small- and medium-sized enterprises and individuals, we provide evidence that commercialization through licensing/selling is the most efficient way of generating knowledge diffusion. We also find some support for new ventures being an important source of knowledge spillovers.