This is the first book on proportionality in Latin American constitutional law. Leading scholars in the region explore how proportionality analysis has become a key part of the constitutional law of a region where, almost paradoxically, constitutions with clear transformative intentions coexist with the highest indicators of social inequality in the world. In this book, scholars, practitioners and students will find a fascinating account of how proportionality has been a central concept in Latin America’s constitutional struggles to curtail excessive uses of state power. The book illustrates how, more recently, proportionality has played an important role in national processes of constitutionalization and transitional justice, and how its current uses in the domain of social rights endow it with a distinctive meaning and role in regional constitutionalism. This pioneering book opens up the space for a much needed global conversation on how Latin America has decisively contributed to comparative constitutional law.