In this paper, we seek to contribute theoretically to the literature on horizontal institutional inter-linkages in global environmental governance by framing such inter-linkages as regime conflicts that are embedded in and shaped by overarching governance norms. Our definition of regime conflicts stresses the legal and behavioural conflicts that are immanent to any regime inter-linkage. Furthermore, it allows for an analytical distinction between inter-linkages per se (i.e. a positional difference) and their consequences (i.e. subsequent processes such as the management of a conflict). This allows for theory-driven analyses and predictions of these consequences. We further argue that such conflicts among international regimes are embedded in a broader normative context. Regime conflicts are an articulation of ongoing contestations over broader norms, practices and objectives. Building on these concepts of regime conflicts and norm collusion, our paper targets a particular consequence of regime inter-linkages. We ask to what extent overarching global governance norms (and conflicts among them) shape regime development in general, and specific rules on overlapping issues among regimes in particular. We pursue this research question for three cases of potential regime conflicts: between the UN climate regime and the World Trade Organization; between the UN climate regime and the Convention on Biological Diversity; and between the Convention on Biological Diversity’s Cartagena Protocol on Biosafety and the World Trade Organization. For all three cases we find a dominance of the norms of neoliberal environmentalism, which has fostered inclusion of market-based approaches into the environmental regimes involved in these conflicts. However, we also identify considerable variation across the three cases: the dominance of neoliberal environmentalism has also been contested by other overarching global norms. This contestation has led to the inclusion of alternative norms in the involved regimes. We conclude by assessing the consequences of this for theoretical study of regime inter- linkages.