Federalism presents a dilemma for the implementation of international human rights law in those African states that operate federal constitutions. Central governments in these states enjoy international legal personality, make treaties and represent their states as parties to those treaties, yet internal legislative competence over some issues regulated by treaty is commonly shared between central and regional governments. Consequently, while central governments bear responsibility for transforming international standards into national law, challenges arise in areas such as the protection of children from child marriage, where they lack exclusive national legislative competence. How have these states managed to implement international law without violating their own constitutions? Applying a comparative approach, this article argues that African federal states have employed two main models to overcome the dilemma, neither of which has been totally effective. Drawing lessons from federal states outside Africa, the article suggests other mechanisms to perfect Africa's two main models.