Complex assessment tasks and pedagogies present barriers to the learning and achievement of students with disability, including those with language and/or attentional difficulties. This research will test: 1) whether accessible assessment task design leads to improved student outcomes; 2) whether enhancing teachers’ inclusive practice improves student access to formative assessment pedagogies, enabling more accurate student understanding of assessment aims and requirements; and 3) how improvements in task design and teacher practice can be sustained and upscaled across secondary school departments. Expected outcomes of international significance are more inclusive learning and assessment practices with the potential to benefit all students.