Standards for Internal Control in the Federal Government (commonly known as the “Green Book”), sets the standards for an effective internal control system for federal agencies and provides the overall framework for designing, implementing, and operating an effective internal control system that safeguards public resources.
Managers throughout the government use the Green Book to help them achieve their entity's mission. GAO updated the Green Book in 2025 to provide requirements, guidance, and resources to help managers better address risk areas related to fraud; improper payments; information security; and the implementation of new or substantially changed programs, including emergency assistance programs.
Updates include an emphasis on prioritizing preventive control activities and highlighting management’s responsibility for internal control at all levels within the entity’s organizational structure, such as program and financial managers.
Federal executive branch agencies are required to establish internal controls in accordance with the standards in the Green Book. The Green Book may also be adopted by federal agencies outside the executive branch and by nonfederal groups (such as state, local, and quasi-governmental agencies and nonprofit organizations) as a framework for an internal control system.