Developing a national GHG inventory requires robust institutional arrangements, quality inputs (data, emission factors), understanding of the appropriate calculation methods, and capacity to compile a complete report. Developing countries continue to face challenges at each step of the GHG inventory development process, including the process to establish and apply quality assurance and quality control. With a view to overcoming this challenge, the secretariat, with the support of the Global Support Programme (GSP) for National Communications and Biennial Update Reports (GSP), prepared this guide with the objective of: a) Providing clear guidance for the peer-review of national GHG inventory reports and national GHG inventory management systems, to achieve higher quality reporting, through the use of Quality Assurance and Quality Control procedures in a non-intrusive or punitive manner; b) Achieving enhanced capacity of national experts involved in the process of the preparation of national GHG inventories to develop high quality, transparent, national GHG inventory reports and maintain sustainable national GHG inventory management systems; c) Facilitating the enhanced process of Quality Assurance (QA) and Quality Control (QC) of national GHG inventory reports, both across countries (peer-review) and within countries (expert-review).