The National Inventory Report 2023 (NIR 2023) gives a detailed and comprehensive description of the trend and the methodologies applied in the Austrian air emissions inventory for the greenhouse gasse carbon dioxide, methane, nitrous oxide, HFC, SF6, and NF3. With this report, Austria complies with its reporting obligations under the EU Governance Regulation No 2018/1999 as well as the UNFCCC by providing transparent and verifiable documentation. It contains emission data by sector for the years 1990-2021 as well as information on emission factors, activity data and other basic datafor emission calculations. Moreover, the report provides documentation of the national inventory system and quality control and assurance activities as performed by the accredited Inspection Body for Emission Inventories (ISO/IEC 17020).