This report introduces the Global Electricity Regulatory Index (GERI), an index which benchmarks a country's existing regulatory system against theoretical best practice, based on a set of standardized indicators which permit meaningful cross-country comparisons and provide the potential for progress with regulation to be tracked over time. The resulting snapshot of regulatory performance reveals that important progress has been made, but at the same time highlights many remaining significant gaps and shortcomings in the regulatory environment for the power sector in the developing world.