This book arises from the need to understand the factors that enable the expansion of religious freedom in Mexico and Colombia. My research stands out by utilizing a public policy approach and operationalizing the conceptual category I propose: the expansion of religious freedom. Throughout the book, I classify the definitions of religious freedom (skeptical and conventional) and apply public policy approaches such as policy change and policy transfer. My goal is, on the one hand, to identify the moments that drive the expansion of this right and, on the other, to propose improvements to public policies on religious freedom, which often present ambiguous problems and diffuse actions in promoting and guaranteeing this right. I hope that readers find in this work not only a rigorous analysis but also a practical tool for building more effective and just public policies in the realm of religious freedom. I trust that the contributions of this book will inspire similar studies in other contexts.