Long a staple in the toolkit of American politics, comparison among subnational territorial units has gained increasing currency in comparative politics. A growing portion of subnational research, especially in the monographic literature, employs comparisons of subnational territorial units within different countries. This approach to comparison, which I term transnational comparison, has the potential to build on and extend the advantages of subnational comparison. Despite the numerous added challenges it poses, transnational comparison offers a variety of ways to incorporate and leverage variations between countries as well as within them. Drawing on exemplary studies from the literature on subnational regimes and beyond, I outline a typology of successful transnational comparative strategies. The choice among these strategies depends on their distinctive properties, on the substantive questions asked, and on the stage of a research program. All have contributed to advancing the study of politics beyond nation-centered comparison.