Philosophical literature hitherto on the ontology of artifacts—that is, broadly speaking, essentially functional objects that depend on humans for their existencesor functions—has by and large accepted, at the outset, two closely-related axioms as given: First, ordinary, "garden-variety" artifacts are ontologically distinct from social and institutional kinds in substantive ways. Second, artifacts' dependence on humans is dependence on the intentions or interventions of their authors and their authors alone. This dissertation critically challenges both claims. I reject the presumed division between social and institutional artifacts versus ordinary non-social-intentional artifacts, contending that there is in fact a continuum between them. I argue that seemingly ordinary artifacts often play institutional-functional roles in social institutions by contributing to the self-reproduction of those institutions. Furthermore, I argue that an explanatorily adequate ontology of artifacts that accounts for their existences, functions, and our behavioral phenomenology around them must appeal to intentional sources beyond the minds of their authors. In particular, I argue that artifacts, even ordinary ones, ontologically depend on social intentionality. In support of my claim, I offer a focused analysis of the dependence relationship through a special case of artifacts, works of art. At last, I defend Function Essentialism about artifacts against recent challenges and argue that it remains the most viable approach among our currently available alternatives.