The linkage between the impact of assessment and compliance with children's rights is a connection, which although seemingly obvious, is nonetheless rarely made, particularly by governments, which, as signatories to the relevant human rights treaties, have the primary responsibility for ensuring that educational practice is compatible with international children's rights standards. While some jurisdictions are explicit about an adherence to children's rights frameworks in general policy documentation, such a commitment rarely features when the focus is on assessment and testing. Thus, in spite of significant public and academic attention given to the consequences of assessment for children and governments committed to working within children's rights standards, the two are rarely considered together. This paper examines the implications for the policy, process and practice of assessment in light of international human rights standards. Three key children's rights principles and standards are used as a critical lens to examine assessment policy and practice: (1) best interests; (2) non-discrimination; and (3) participation. The paper seeks new insights into the complexities of assessment practice from the critical perspective of children's rights and argues that such standards not only provide a convenient benchmark for developing, implementing and evaluating assessment practices, but also acknowledge the significance of assessment in the delivery of children's rights to, in and through education more generally. (Contains 1 table and 3 notes.)