While the decarbonisation of the global economy will bring immense benefits in the aggregate and to many individuals, it will also be disruptive and costly for some, at least in the short term. As these disruptions and costs have become increasingly salient in recent years, there has been an explosion of interest in the climate policy community about how low-carbon transitions can be implemented justly, equitably, and politically smoothly. A key part of what is needed in responding to this growing interest is a better understanding of the suite of 'transitional assistance policies' and strategies that can be deployed, alongside or as part of climate change mitigation policies and processes. Responding to this need, we survey a wide, multidisciplinary literature to answer the 'who', 'what' and 'how' of transitional assistance policy: who is likely to be adversely affected by the low-carbon transition, and in what ways? What substantive strategies and policy instruments are available to governments to mitigate the burdens of low-carbon transitions? And how can governments implement such strategies and policies successfully? In the course of answering the first two of these questions, we develop a novel typology of transitional assistance policies, in which multiple policies are parsimoniously classified according to one of four coherent policy strategies, and one of five kinds of beneficiaries. In answering the third question, we emphasise the importance of certain 'state capacities' for shaping transition processes and managing vested interests. Key policy insights: Without transitional assistance policies, consumers, workers, businesses, speciallyaffected communities, and states that are highly dependent on emissions-intensive assets stand to lose from decarbonisation. Transitional assistance policies can be narrow (addressing financial losses only) or broad (addressing a wider range of losses), and backward-looking (conservative) or forwardlooking (adaptive). Combining these elements yields four coherent transitional assistance strategies: compensation; exemption; structural adjustment assistance; and comprehensive adaptive support. Comprehensive adaptive support strategies have greatest potential for just, equitable and smooth transition outcomes, but are costlier and more complex to implement. State capacities to steer complex, long-term transitions are therefore a crucial variable in transition success. Just transition; climate change mitigation; transitions; structural adjustment assistance; compensation; state capacities Acknowledgements: the authors are grateful to Adrien Vogt-Schilb, Emily Tyler and three anonymous referees for helpful comments. Funding information: FG gratefully acknowledges support by the Coal Transitions project managed by IDDRI and Climate Strategies, with funding provided by the KR Foundation, and distributed via the Centre for Climate & Energy Policy at the Australian National University. AG gratefully acknowledges funding from ClimateWorks Foundation. limited alternative ...