Cultural background can influence cognition, including executive functions (EFs), abilities that encompass skills responsible for self-regulation of thoughts and behavior. The seminal unity and diversity model of EFs proposes the existence, in adulthood, of at least three correlated but separable EF latent (shared variance in more than one task/indicator) domains: inhibition, updating and shifting. However, evidence of the cross-cultural generality of this framework is lacking, especially in adolescence, an age during which these domains become more clearly separable. We tested whether this EF fractionation could be observed in early adolescents (9- to 15-year-olds) from metropolitan areas in Brazil (São Paulo) and Iran (Tehran) (total sample: 739; 407 Iranians; 358 girls). Participants carried out two open-access tasks that are representative of each EF domain and that were adapted to each cultural context. Seven latent model configurations were tested. The three-correlated latent factor structure had adequate fit, and multiple-group confirmatory factor analysis invariance testing showed invariance for country at the level of the latent factor structure (configural), factor loadings (metric), and partial invariance at the intercept (scalar) level. Iranians had higher scores in all domains. Multiple indicators multiple causes invariance testing showed model invariance across age (except for one task) and parental education. Performance in all domains improved with age and only minimally with parental schooling. We conclude that EF fractionation into three domains is present in the first half of adolescence in two samples from underrepresented populations in the literature, suggesting a potential generality of EF latent unity/diversity development at this age.