Policy monitoring has been gaining importance in energy and climate gover-nance. It is currently being heralded as a key solution for coordinating energygovernance not only regionally in the emerging Energy Union in the EuropeanUnion (EU), but also globally in the Paris Agreement on climate change. Thecore idea is that transparency through monitoring will incentivize actors to adoptpolicy pathways toward mutually agreed long-term energy and climate policygoals. In addition, monitoring of key indicators (e.g., use of certain kindsof energy), in particular, sectoral contexts, may be a necessary precursor toevaluation and improved regulation. This chapter unpacks the concept of monitoring, reviews the emergence of energy and climate policy monitoring inthe EU, and then details experiences with concrete monitoring regimes in differ-ent settings related to energy and climate policy, ranging from the United Nations(UN) to the EU, as well as nation states and nongovernmental actors. In so doing,it highlights various strands of emerging research and knowledge on monitoringstructures, steering effects and costs, but also the need for further work, especiallyregarding usage and impact. Issues related to politics, coordination, and resourcesare likely to challenge monitoring regimes; further investigation should focus onthe efficacy of monitoring systems, which many assume, but few haveresearched.