This report presents six core principles of inclusive assessment and accountability systems with a brief rationale and specific characteristics that reflect each principle. The principles are: (1) All students with disabilities are included in the assessment system; (2) Decisions about how students with disabilities participate in the assessment system are the result of clearly articulated participation, accommodations, and alternate assessment decision-making processes; (3) All students with disabilities are included when student scores are publicly reported in the same frequency and format as all other students, whether they participate with or without accommodations, or in an alternate assessment; (4) The assessment performance of students with disabilities has the same impact on the final accountability index as the performance of other students, regardless of how the students participate in the assessment system; (5) There is improvement of both the assessment system and the accountability system over time, through the processes of formal monitoring, ongoing evaluation, and systematic training in the context of emerging research and best practice; and (6) Every policy and practice reflects the belief that all students must be included in state and district assessment and accountability systems. (Contains 11 references.) (CR)