This chapter presents the topic of Part III and the contributions of the chapters included in this Part of the book. The focus of the chapter is on assessment culture, as constructed in classrooms and schools, and on the processes of co-regulation of student learning in relation to assessment for learning (AfL). Co-regulation is defined as the joint influence of student self-regulation and of regulation from other sources (in particular, teachers, peers, assessment procedures, and tools) on the progression of student learning. Summaries of the Part III chapters highlight the new perspectives and the research evidence presented by the authors. A concluding synthesis examines the proposals made by the authors regarding ways of meeting the challenges of AfL implementation. Particular attention is given to professional development and policy measures that are likely to enhance teachers' capacity to implement AfL practices and students' active involvement in these practices.