ABSTRACT Stigmatisation of mental illness and substance use disorders has negative health implications. Previous research suggests that religious fundamentalism relates to stigmatising attitudes; Christian evangelicalism, as one type of fundamentalism, is a prevalent influence on personal belief systems in the United States. We recruited 380 participants from Amazon’s Mechanical Turk, who self-identified as evangelical or non-evangelical, read vignettes depicting schizophrenia, alcohol use disorder (AUD), or asthma (control), and completed a stigmatisation measure. Notably, about a quarter of the non-evangelical group were non-religious individuals. Evangelicals had higher stigmatisation of schizophrenia and asthma, but no between-group difference was found regarding AUD. Higher stigmatisation of schizophrenia among evangelicals might reflect perceived violations of societal and religious norms, while widespread stigmatising attitudes related to AUD in the general population might explain the comparable stigmatisation of AUD among both groups. These findings highlight the importance of considering evangelical religious beliefs in stigma research and anti-stigma interventions.