Tackling climate change, addressing other environmental threats, and achieving the green transition all require the profound transformation of network sectors such as water, energy, e-communications, and transport. As leading public bodies in the governance of network sectors, economic regulators can significantly affect environmental outcomes. This publication discusses the role of economic regulators and the tools they can use to contribute to environmental sustainability and the green transition in the sectors they oversee. Survey data and information gathered in collaboration with the OECD Network of Economic Regulators is used to analyse the use of such tools and regulator's governance arrangements, highlighting a number of common challenges and opportunities. The publication includes data relating to regulators' objectives, powers and functions, mechanisms for co-ordination, use of regulatory management tools, and levels of capacity and resources, and integrates OECD guidance related to these topics. As such, this publication will prove valuable to economic regulators, governments and legislators with relevant responsibilities.