Testing accommodations allow students with disabilities to both participate in and demonstrate their knowledge and abilities on statewide assessments. This article discusses accommodation-related research findings of a 3-year federally funded research study. The data analysis includes an examination of accommodation policies and discipline rates in all 50 states, participation rates in states for which data were available, and the relationships among these data as indicated by statistical correlations. Also, a detailed discussion of the proctor/scribe accommodation is included, because it correlated more strongly with higher participation rates than any other specific accommodation. Implications of these findings for students, parents, policymakers, and practitioners are discussed.