Many multilateral environmental agreements have adopted differentiated rules for different countries, based on the recognition of the ‘common but differentiated responsibilities’ (CBDRs) of states. By establishing two rigid groups of countries with and without emissions reduction obligations, the intergovernmental climate regime represents the most extreme case of such differentiation. The regime has struggled to overcome this rigidity and the resulting political deadlock between developing and developed countries. Transnational climate governance (TCG) initiatives have emerged as an alternative to provide mitigation, adaptation or finance outside the multilateral process. By drawing on synergies between public and private actors, it is hoped that they overcome the paralysis of the intergovernmental process. Yet, they take place in the same world of unequal peers, with different levels of capacity and responsibility for climate change. This article investigates the extent to which such TCG initiatives reflect the CBDR principle. Do different types of initiative – involving different types of actor or with different climate-related goals – address differentiation in distinct ways? Does taking account of CBDRs affect the membership of transnational initiatives? This article explores these questions empirically by analyzing a sample of TCG initiatives in terms of how they include differential treatment of states and non-state members. It concludes that TCG initiatives address differentiation in a pragmatic way. Most frequently, they either offer participants flexibility in how to implement their commitments, or provide support to members from developing countries. Such support is, so far, still insufficient to address the limited involvement of developing country actors.