Purpose:The aim of this study is to compare substance use and school-based stressors among Black and Latinx transgender youth (trans BLY), White transgender youth (trans WY), and Black and Latinx cisgender youth (cis BLY) and identify associations between substance use and stressors among trans BLY.Methods:We analyzed 2015—2017 Biennial California Healthy Kids Survey data with a weighted sample of the state’s secondary school population. The analytic sample included 9th and 11th grade trans BLY, trans WY, and cis BLY. Past 30-day and lifetime substance use (cigarettes, e-cigarettes/vaping, marijuana, and alcohol) and school-based stressors (victimization, race-, gender-, and sexuality-based harassment) were compared between cohorts via logistic regression. For trans BLY, associations between substance use and stressors were assessed via logistic regression.Results:The analytic sample (n = 19,780) included 252 trans BLY, 104 trans WY, and 19,424 cis BLY. Among trans BLY, estimated prevalence of 30-day (and lifetime) use of cigarettes, e-cigarette/vaping, marijuana, and alcohol were 13% (23%), 19% (39%), 27% (42%), and 29% (48%), respectively. Trans BLY had similar odds of 30-day and lifetime use of all substances compared to trans WY but higher odds of use compared to cis BLY. For trans BLY, race- and gender-based harassment and higher victimization levels were associated with higher odds of 30-day and lifetime use of all substances. Sexuality-based harassment was associated with higher odds of 30-day and lifetime marijuana and alcohol use.Discussion:Trans BLY have high prevalence of substance use, comparable with trans WY but higher than cis BLY. Substance use among trans BLY is associated with school-based stressors.