Smart wearable technologies have seen an explosive growth over recent years, with some research indicating that the wearable technology industry is expected to grow from USD 24 billion today to over USD 70 billion in 2025. This proliferation has extended across disparate domains, ranging from medical applications and fitness and social technologies to military, industrial, and manufacturing applications. As with any emergent technology, these wearables present opportunities for our moral benefit as well as moral challenges to be addressed. A crucial dimension of this discussion is the ethical evaluation of the impact of smart wearables on the autonomy of human decision-making. Nowhere is this a more pertinent concern than when dealing with persons uniquely vulnerable to autonomy infrin¬gement. This contribution, undertaken from an explicitly normative and ethical perspective, investigates the potential impact of smart wearables on various dimensions of the decisional autonomy of vulnerable persons. This article is part of the anthology “Artificial Intelligence, Democracy, and Privacy”.