We aimed to determine whether early adolescents who report higher levels of teacher connection have a greater prevalence of flourishing and whether this association is present across levels of parent connection. We analyzed cross-sectional data, collected in the International Survey of Children's Well-Being (2016-2019), from 33,269 11- to 13-year-olds in 25 countries. The teacher connection score, analyzed as quartiles, asked about care, support, and respect from teachers. The flourishing score (range 0-10) was based on items about self-acceptance, purpose in life, positive relations, growth, environmental mastery, and autonomy. The prevalence (95% confidence interval) of flourishing (score > 8) was 66.0% (65.4%, 66.5%). The covariate-adjusted difference in flourishing prevalence between those in highest and lowest quartiles of teacher connection was 26.8% (25.2%, 28.5%). This difference was similar across groups with varying levels of parent connection. Teacher connection may contribute to adolescent flourishing, in addition to academic achievement and the avoidance of negative outcomes.