It is evident that Australasia is in need of a research agenda that critically analyses the impact and use of national external and international assessments, as well as issues related to classroom-based assessment. Although these are investigated at many levels, the question remains: Are we assessing what we really need to assess? Issues remain in relation to what national and international testing reports to the community, as well as validity issues around how it is used, and accountability. In addition, school-based assessment includes assessment “of”, “as”, and “for” learning with pockets of research applying a fine-grained review. The role that technology plays in classrooms and large-scale assessments is worthy of continued exploration in the light of available and changing tools. Assessment in the mathematics classroom has the potential to alter the experiences of children in our schools at every level. This chapter provides a balanced review and critique of research related to assessment completed within the timeframe of this review. The authors position the discussion in the context of current agendas and consider the impact the mathematics education community has had to date, and the future potential of the community to inform assessment practices and wider discussion.