Agency is the human capacity to freely choose one’s thoughts, motivations and actions without undue internal or external influences; it is distinguished from decisional capacity. Four well-known conditions that can deeply affect agency are depression, demoralization, existential distress, and family dysfunction. The study reviews how they may diminish agency in persons whose circumstances may lead them to consider or request euthanasia or assisted suicide. Since agency has been a relatively neglected dimension of autonomous choice at the end of life, it is argued that to respect the autonomy of individuals, it is essential to establish their agency.