An increasing number of countries are considering the use of climate policy instruments to achieve mitigation commitments. Greenhouse gas benchmarks have been used in climate policy instruments to set targets and thresholds for environmental performance, and to determine the distribution of instrument benefits and obligations. This guidebook is intended to provide policymakers with structured guidance on the development of benchmarks and draws on over a decade of global experiences in benchmark development, covering practices in 16 jurisdictions that are already using, or are in the process of developing, a benchmarking approach.