Research has indicated the integral role of self-efficacy in boosting learner engagement. Yet, little research on this issue has been conducted in the field of L2 writing. The purpose of this quantitative study is to explore how EFL learners' L2 writing self-efficacy affects the level of their engagement with teacher and peer written corrective feedback (WCF). A sample comprising 227 Taiwanese senior high school students completed two questionnaires: the learner engagement with written corrective feedback scale and the L2 learners' writing self-efficacy scale. The results showed that the participants self-reported a low-to-moderate level of L2 writing self-efficacy. In addition, when all three subtypes (i.e., ideation, conventions, and self-regulation) of L2 writing self-efficacy were taken into account, self-efficacy for writing self-regulation was the only variable with predictive power for learner engagement with teacher and peer written corrective feedback. The findings further our understanding of EFL learners' L2 writing self-efficacy and of the under-researched topic of the relationship between L2 writing self-efficacy and learner engagement with written corrective feedback.