This study explored juror stigma towards defendants with mental illness (MI), and examined the impact of education on juror decision-making in Not Criminally Responsible on account of Mental Disorder (NCRMD) cases in Canada. Four-hundred and eighty-six participants received two forms of education (MI or diabetes, and NCRMD or duress), read an NCRMD trial transcript in which the defendant’s MI was manipulated, and provided a verdict (NCRMD or guilty), defendant perceptions, MI attitudes, and NCRMD attitudes. Continuous analyses revealed that MI and NCRMD education did not have a combined
effect on defendant perceptions, MI stigma, or decision-making in NCRMD cases. Path analysis revealed that MI type was directly and indirectly related to guilt certainty via MI attitudes and defendant perceptions. However, NCRMD attitudes did not have an effect on verdicts. Results imply that MI attitudes are deeply ingrained in social and cultural norms and are not amenable to change despite education.