Objectives: Examine trends in diabetes-related knowledge, perceptions, and behavior among U.S. adults with and without a diagnosis of diabetes and among subpopulations at risk. Discuss implications for national diabetes education and for the National Diabetes Education Program (NDEP) in particular. Methods: Three population-based NDEP National Diabetes Surveys (2006, 2008, and 2011) collected information on diabetes knowledge, education, and self-management; perceived and actual risk of diabetes; and lifestyle changes. Results: Since 2006, U.S. adults significantly advanced their knowledge and awareness of diabetes and prediabetes. Perceived personal risk did not increase among people with prediabetes (PWP) or people at risk. Family history as a risk factor dropped in reported importance, especially among PWP and Hispanics. Diabetes self-management rose modestly, although checking blood sugar significantly declined. Trends in understanding the diabetes and cardiovascular disease link, A1C testing, and adjusted logistic regression results for perceived risk are discussed. Discussion and Implications: Although diabetes-related knowledge has reached high levels, stagnant perceived risk suggests people at risk are not applying this knowledge to themselves. Future surveys are planned to include additional, specific questions to capture people's movement toward behavior change and to identify where strategic efforts and educational interventions can help promote improved behaviors.