These guidelines support a harmonized international approach to assessing the impacts of livestock on biodiversity. The livestock sector is a major user of natural resources (land in particular) and contributor to pollution (causing nutrient losses and increasing greenhouse gas emissions), which makes it a sector with a high impact on biodiversity. However, livestock production is one of the few sectors with not only negative but also positive impacts on biodiversity. The sector can therefore pull two levers to improve its biodiversity performance - mitigate harm and maximise benefits. Yet many environmental assessments of the livestock sector have not addressed biodiversity because of its intrinsic complexity. These guidelines, developed by the Technical Advisory Group on biodiversity - a team of 25 international experts in ecology, biodiversity indicators, agronomy, and environmental science - strive to include biodiversity in such assessments, to improve understanding of livestock's impact on biodiversity and to reveal possible synergies or trade-offs with other environmental criteria and the Sustainable Development Goals.