Oaks (genus Quercus) are found in forests and shrublands across the Northern Hemisphere that include biodiversity hotspots in tropical and subtropical regions, such as Mexico and Southeast Asia. In these habitats, oaks are often keystone species, shaping ecological relationships and providing multiple ecosystem services and economic benefits. Unfortunately, many oak species are declining and until recently, there was not a complete account of the conservation status of oaks globally. To address this need, staff at The Morton Arboretum partnered with Botanic Gardens Conservation International (BGCI), the IUCN SSC Global Tree Specialist Group, and the Global Tree Assessment (GTA) to conduct IUCN Red List assessments for all the oaks of the world. The resulting Red List of Oaks 2020 revealed that 50% of the world’s oak species (217/430) are of conservation concern, including 112 species assessed as critically endangered, endangered, or vulnerable. What is more, 67 species were assessed as data deficient, highlighting the urgent need for further research, particularly in the tropics. Although oaks are native to 90 countries, the highest species richness for the genus is in Mexico (164 species), China (117), the United States (91), and Vietnam (49). These countries also had the highest number of threatened species at 32, 36, 16, and 20, respectively. Major threats to oaks globally included land use change, a changing climate, and native and non-native pests and diseases. Once armed with the assessment data, staff at Morton were able to prioritize species and regions to develop and conduct in situ and ex situ conservation projects, such as efforts to study and prevent extinction of the endangered oak Quercus Brandegeei in Mexico. This Global Trees Campaign (GTC) project brought together Mexican scientists, international partners, land managers and community members who are working together towards a science-based, stakeholder-inclusive recovery action plan for the species. Although these single-species projects are extremely valuable and provide important case studies, a coordinated, global effort is needed to safeguard the >200 species of oaks at risk. Led by the Morton Arboretum in collaboration with BGCI and dozens of other partners, the Global Conservation Consortium for Oak (GCCO) was launched to translate and amplify the GTA results into action. Members are working collaboratively to develop and implement a comprehensive conservation strategy to prevent the extinction of the world’s oaks.