As in prior years, the National Defense Authorization Act for Fiscal Year 2021 contains a variety of provisions setting U.S. Department of Defense priorities for energy, environmental, and natural resource issues. These include measures that represent some degree of consensus on these often-politicized topics. In this Article, the fourth in an annual series, the authors canvass how the Act addresses a host of issues in the areas of climate resiliency, energy management, hazardous substances, and environmental and natural resource management, and its implications for practitioners in these areas.