Mandatory child abuse reporting laws have developed in particular detail in the United States, Canada, and Australia as a central part of the governments' strategy to detect cases of abuse and neglect at an early stage, protect children, and facilitate the provision of services to children and families. However, the terms of these laws differ in significant ways, both within and between these nations, with the differences tending to broaden or narrow the scope of cases required to be reported and by whom. The purpose of this article is to provide a current and systematic review of mandatory reporting legislation in the 3 countries that have invested most heavily in them to date. A comparison of key elements of these laws is conducted, disclosing significant differences and illuminating the issues facing legislatures and policymaking bodies in countries already having the laws. These findings will also be instructive to those jurisdictions still developing their laws and to those that may, in the future, choose to design a system of mandatory reporting.