For individuals with mental disorders, public stigma around mental illness exacerbates maladjustment and reluctance to seek treatment, contributing to poor quality of life beyond the effects of the disorder itself. Previous research demonstrates small, albeit significant, effect sizes for stigma reduction interventions. The current meta-analysis examines the effects of interventions on the cognitive, affective, and behavioral components of stigma around mental illness. Forty randomized controlled trials of interventions to reduce public stigma were included. Across studies, results demonstrated significant postintervention changes in stereotypic cognitive beliefs about mental illness (k = 33, Hedge’s g = 0.29, p k = 8, g = 0.26, p = .025), and behavioral intentions toward individuals with mental illness (k = 24, g = 0.54, p k = 15, g = 0.31, p k = 14, g = 0.41, p = 0.001), but not for affective responses (k = 6, g = 0.20, p = 0.15). Type of intervention, target population, mental illness type, age, duration, and delivery medium moderated effects for some stigma components. As only three studies examined mediators of treatment effects, we know little about the mechanisms through which interventions work to reduce public stigma and the reasons for differential intervention effects on cognitive, affective, and behavioral stigma. Implications of findings and future directions are discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved)