The assessment of educational progress and outcomes of pupils is important to all concerned with education. This includes testing which is undertaken for accountability and award bearing purposes. This article examines how students with special educational needs and disability (SEND) are included in assessment. An "inclusive assessment" framework is outlined based around three core features: (1) all students are included and benefit from assessment; (2) assessments are accessible and appropriate for the diverse range of children in the education system; and (3) the full breadth of the curriculum is assessed (including curriculum areas of particular relevance to students with SEND). Assessment policies and practice in three countries (England, Ireland and the US) are drawn upon to demonstrate how the framework usefully enables between-country comparisons and within-country analysis. This analysis shows that in comparison to Ireland, the US and England have highly developed system-based approaches to assessment which seek to "include all" (feature 1) and be "accessible and appropriate" (feature 2). However, the analysis highlights that a consequence of such assessment approaches is the narrowing of the curriculum around topics that are assessed (most notably literacy and mathematics). Such approaches therefore may be at the expense of wider curriculum areas that have value for all students, but often of particular value for those with SEND (feature 3). It is argued that within such systems there may be a danger of neglecting the third feature of the inclusive assessment framework, i.e. ensuring that the full breadth of the curriculum is assessed. A consequence of such an omission could be a failure to assess and celebrate progress in relation to educational outcomes that are relevant to a diverse range of students.