Background With growing numbers of countries legalizing euthanasia or assisted suicide (EAS), there is a debate as to whether EAS should also be available to people with severe, treatment-resistant mental illness. Excluding mental illness as a legitimate reason to receive EAS has been framed as discriminating against people with mental illness. Aims We examine whether approval or opposition to psychiatric EAS are related to stigma toward people with mental illness. Method We asked a representative sample of the general population in Germany (N = 1515) whether they would approve of EAS for someone with severe, treatment-resistant mental illness. Stigma was assessed with the Value-Based Stigma Inventory (VASI), addressing rejection of people with mental illness in relation to different personal values. Results A total of 19% of the German population approved of psychiatric EAS. Higher stigma scores were associated with greater approval of EAS (Spearman rank correlation coefficient, 0.28; P < 0.001). This association held true when controlling for sociodemographic variables. It was strongest for stigma related to perceived threats to one's security, reputation and meritocratic values. Conclusions Our results highlight that, although opposing psychiatric EAS is sometimes framed as discriminatory, approval of psychiatric EAS might also carry hidden, stigmatising motives. To avoid any unintended negative consequences for people with severe, treatment-resistant mental illness, any legislation on psychiatric EAS needs to be crafted with particular caution.