The emergence of Positive Psychology in second language acquisition has placed greater emphasis on the vital role of engagement in learning English as a foreign language (EFL). Although previous research has established that EFL learners' engagement is affected by ideal L2 self, boredom, and grit respectively, sporadic studies have attempted to address the simultaneous link between these factors and engagement. To fill the gap, this study aims to examine the association between the ideal L2 self and engagement among EFL learners, with a special focus on the mediating role of grit and boredom in the relationship. A total of 466 EFL learners were enrolled in two public universities in Northern China. Structural equation modeling (SEM) results revealed that grit positively predicted engagement and mediated the relationship between the ideal L2 self and engagement. Moreover, boredom negatively predicted engagement and acted as a mediator between the ideal L2 self and engagement. However, ideal L2 self did not directly predict engagement. These findings contribute to the current knowledge by elucidating the complex relationships between the three factors and engagement, which can provide insights for pedagogical practices and directions for future research.