Many comparative constitutional law scholars have listed constitutional rights and studied their historical development. However, as new waves of constitution-making arise, new rights emerge too. This article argues that future generations are a new holder of legal interest in constitutions worldwide, a consequential phenomenon that has been overlooked by the literature thus far. By looking at all national written constitutions, historical and contemporary, we present a chronology of the constitutionalization of future generations and show how they went from a handful to 41% of all constitutions as of 2021 (81 out of 196). Through content analysis, we show how they have gradually become part of a modern, universalist language of constitution-making and have reframed older rights from abstraction into the protection of people in the future. We also assess the strength of these provisions, analyzing their de jure intensity and de facto repercussions, the latter through case studies from all over the globe.