Oil and gas supplies will continue to play a key role in a future sustainable energy system to support economic growth and social progress, even under a scenario in which stringent climate policies and measures are implemented. At the same time, oil and gas industries are among the main sources of anthropogenic methane emissions. Methane is the primary component of natural gas, with some emitted to the atmosphere during its production, processing, storage, transmission, distribution, and use. Despite methane’s short residence time, the fact that it has a much higher warming potential than CO2 and that its atmospheric volumes are continuously replenished make effective methane management a potentially important element in countries’ climate change mitigation strategies. This document provides guidance for developing and implementing effective monitoring, reporting and verification (MRV) practices, as well as for mitigating methane emissions, from the oil and gas sector. In its discussion on MRV and mitigation opportunities, it is meant to serve as a resource for a broad audience, including owners and operators of oil and gas facilities and policymakers at all levels of government. It is intentionally “principles-based”, recognizing that conditions vary greatly across oil and gas facilities, and that legal, political and institutional aspects differ by jurisdictions.