Predicting academic performance is of key importance to the success, wellbeing and \nprosperity of students, their families, the economy, and the society at large. This study \ninvestigates the relationship between academic engagement, psychological capital (PsyCap) and \nacademic performance. Data were collected in two different universities, one in Spain and \nanother in Portugal. Students completed two self-report questionnaires regarding academic \nengagement and Psychological Capital. Academic performance was assessed through Grade \nPoint Average, provided by the universities at the end of the exam period. The samples consisted \nof 389 and 243 undergraduate students, respectively. Results showed a positive relationship \nbetween academic engagement and PsyCap, on the one hand, and academic performance on the \nother, in both samples. Results also supported PsyCap as a full mediator in the relationship \nbetween academic engagement and academic performance. Exploration of alternative models \nyielded superior fit for the proposed model. Accordingly, academically engaged students were \nlikely to experience higher levels of PsyCap, which in turn positively impacted their academic \nperformance. The results point to the importance of considering psychological predictors, rather \nthan the prevalent reliance on traditional predictors of academic performance.