This book explores when, why, and how regional organizations adopt and design institutions to promote and protect fundamental standards of democracy, human rights, and rule of law in their member states. These regional institutions have spread globally. While their institutional designs have become increasingly similar over time, regional particularities persist. The book identifies factors that generate the demand for regional institutions and shape its institutional design. The argument combines hitherto juxtaposed explanatory factors of demands and diffusion by integrating them in a single framework and clarifying under what conditions the interplay between demands and diffusion plays out in the adoption and design of regional institutions. The book provides a comprehensive overview of regional democracy, human rights, and rule of law institutions based on two original datasets and draws on multivariate statistical analysis as well as case studies on the making and change of regional institutions in the Organization of American States and the Organization of African Unity/African Union.