If colleges provide inaccurate or misleading information about, for example, their students' ability to transfer course credits to another college or qualify for a specific certification after graduation, students may have difficulty completing their degree, finding a job in their field, or paying back their student loans. Education is responsible for enforcing a prohibition against colleges making these types of statements, when it determines they meet the definition of "substantial misrepresentation." GAO was asked to review Education's oversight and enforcement of this prohibition. This report examines (1) how Education has organized its oversight activities and enforced this prohibition since the agency created its Student Aid Enforcement Unit in 2016, and (2) the extent to which Education has complete and updated written procedures for enforcing this prohibition. GAO reviewed relevant federal laws, regulations, and Education documents; analyzed Education data for fiscal years 2016 through 2021; and interviewed Education officials. GAO recommends that Education (1) complete written procedures for substantial misrepresentation investigations, including for selecting colleges and conducting investigations; and (2) update written procedures for imposing penalties, as appropriate, on colleges that engaged in substantial misrepresentation. Education agreed with GAO's recommendations.