This chapter considers the relationship between test-based accountability reform and the education of students with special educational needs and disability (SEND) with a particular focus on the role of international comparative tests of student attainment. It reviews the increased role of accountability-based reform and extends to which high-stakes testing at the school level is able to effectively address the needs of students with SEND. The chapter also reviews the role of international comparative tests of student attainment in informing accountability policies at the national level and the extent to which these assessments can include all students, particularly those with SEND. It considers the relationship between test-based accountability policies and the education of students with SEND. The chapter illustrates the issues around inclusion of students with SEND in national accountability-based reform. It examines the inclusion of students with SEND in international comparative assessments of student performance.