The goal of this chapter is to problematise assessment, in particular, the design of assessment tasks and the interpretation, judgement, and grading of student learning. Our intention is to emphasise the importance of assessment literacy for those who are responsible for its conduct, to assist them in recognising and addressing the complex problem spaces in practice. Assessment designs have a significant impact on how students engage with their learning and the quality of the learning. Furthermore, interpreting and grading student learning occupies considerable resources, time, and effort for teachers and students. It is also a high-stake activity that has possible long-term consequences for students. Quality assessment design and trustworthy interpretation and judging of learning outcomes of students’ learning products and performance calls for assessors to possess complex technical, educational, and ethical knowledge and capabilities and to be self-aware and to monitor their own decision making.