This research analysed relationships between perceived teachers' autonomy support and academic success, with self-efficacy and school engagement acting as mediators. This was a survey of 870 students from the Universidad Autónoma de Santo Domingo (Dominican Republic), with a mean age of 26.99 years (SD = 5.09), 50.6% were men. Factor structure for measures was established. Then a structural equation model based on theoretical considerations was estimated. Final outcomes were grades and subjective well-being. Self-efficacy and school engagement were considered mediators, and the exogenous variable was perceived teacher's autonomy support. This initial model fitted the data well, but several theoretically driven modifications were made and a final model was established. Teacher's autonomy has important direct effects on engagement and self-efficacy, and it also was a direct predictor of subjective well-being. Self-efficacy and engagement had direct effects on subjective well-being. Grades were explained by the effects of self-efficacy, cognitive, and emotional engagement. As a conclusion, the main chain of effects hypothesised among the variables fitted the observed data well, and can, therefore, be tentatively supported: self-efficacy and engagement mediate the effects of autonomy support on academic achievement.