Forests are host to most of Earth’s terrestrial biodiversity. The conservation of the world’s biodiversity is thus utterly dependent on the way in which we interact with and use the world’s forests. The role of forests in maintaining biodiversity is also explicitly recognized by the United Nations Strategic Plan for Forests 2017– 2030 and in the ongoing discussions around the forthcoming post-2020 global biodiversity framework under the Convention on Biological Diversity (CBD). In December 2019, the Food and Agricultural Organization of the United Nations (FAO) adopted the Strategy on Mainstreaming Biodiversity across Agricultural Sectors. In October 2020, at its twenty-fifth session, the Committee on Forestry (COFO) requested FAO to conduct a review of biodiversity mainstreaming in forestry and share good practices on solutions that balance conservation and sustainable use of forest biodiversity. This study has the following objectives: assess the state of mainstreaming biodiversity in the forest sector; take stock of existing concepts and tools for integrating biodiversity in forest management; review the range of policy instruments that, beyond legal protection, can enhance biodiversity conservation; and recommend actions to advance biodiversity mainstreaming in the forest sector.