Plastics revolutionized our world, but their unforeseen effects are accelerating many ecological and social crises—polluting both our oceans and our politics. Plastic Legacies gathers scholars of marine biology, psychology, anthropology, environmental studies, Indigenous studies, and media studies to investigate the urgent socio-ecological challenges exacerbated by plastics. Rejecting neoliberal solutions, the contributors argue that collective action is key to securing lasting change.