This study examined the impact of positive psychology variables, namely trait emotional intelligence (EI), positive affect and self-care, on academic engagement (AE) in an online learning environment during COVID-19. The study involved 717 undergraduates in Lebanon and utilised structural equation modelling for data analysis. The results demonstrated that positive affect and self-care mediated the relationship between trait EI and AE. In women, both self-care and positive affect were mediators, whereas in men, positive affect was the only mediator. For students who received a mix of synchronous and asynchronous lessons, both self-care and positive affect mediated the relationship between trait EI and AE. However, for those who received only synchronous lessons, positive affect was the sole mediator. Furthermore, AE significantly predicted academic performance (AP) in both models. These findings suggest the importance of interventions that enhance trait EI, positive emotions and self-care to improve AE and ultimately AP in online learning.