In this paper we argue that W.V. Quine and D.K. Lewis, despite their differences and their different receptions, came to a common intellectual destination: epistemological structuralism. We begin by providing an account of Quine’s epistemological structuralism as it came to its mature development in his final works, Pursuit of Truth (1990) and From Stimulus to Science (1995), and we show how this doctrine developed our of his earlier views on explication and the inscrutability of reference. We then turn to the correspondence between Quine and Lewis which sets the scene for Lewis’s adoption of structuralism vis-a-vis set theory in the Appendix to his Parts of Classes (1990). We conclude, drawing further from Lewis’s correspondence, by arguing that Lewis proceeded from there to embrace in one of his own final papers, ‘Ramseyan Humility’ (2001), an encompassing form of epistemological structuralism, whilst discharging the doctrine of reference magnetism that had hitherto set Lewis apart from Quine.