This article analyzes the significance of regime theory, or regimes theorization, for the field of International Relations. It tries to reflect on theoretical affinities between the two, with an intention to recast regime theory as IR theory. While this may not be surprising given that regime theory has been a standard occupier of IR theoretical space, not much has been systematically written on both evolutionary qualities of regime theory as such, and its changing yet strong pegging to IR theories and approaches. This is where the main contribution of this theoretically oriented article lies. The article proceeds as follows. First, it discusses existing IR theorization of regimes which has coalesced around three specific ‘waves’ of regimes theorization: the neo-neo-convergence regime theory; cognitivism; and radical constructivism/post-structuralism. Second, it assesses heuristic utility of the three waves of regime theorization in relation to possible domains of empirical application. Finally, more general trends in relation to heuristics are discerned and flagged in the conclusion. 

Keywords: regime theory; regimes, theorization, neo-realism, neo-liberal institutionalism, cognitivism, constructivism, post-structuralism, heuristics