This chapter considers systemic corruption. Corruption is widely recognized to be a major social problem, but its characterization continues to be very controversial. Indeed, it is now commonly noted that what is being corrupted need not be an individual person at all but can be an entire social institution. This kind of institutional corruption has, especially in the last few years, come to be seen as ever more central and important. In this chapter, I advocate for a novel theory of this phenomenon, according to which it is the result of an individual or collective agent acting in ways that prevent a social institution from partially or fully fulfilling its function. In turn, the function of a social institution is spelled out in line with presentist social functionalism. The chapter shows that this new theory of institutional corruption is a useful addition to the literature, as it situates the study of this phenomenon in a wider functionalist approach toward the social sciences and does justice to the complexity of institutional corruption—both when it comes to its inherent nature and its moral evaluation.