This qualitative case study (N = 11) explores first-year Chinese doctoral students' metacognitive awareness of task perception and self-efficacy in academic writing. Drawing on data from learning journals in a L2 genre-based writing course for doctoral students in sciences, this study identified a continuum of stages in their reported self-efficacy for academic writing, including low, balanced, and emerging self-efficacy. Students' descriptions of metacognitive awareness of task perception encompassed awareness of rhetorical, content, and linguistic considerations. Analyses of how students reported metacognitive awareness of task perception and their selfefficacy revealed that low self-efficacy tended to co-occur with relatively sophisticated metacognitive awareness of rhetorical considerations, while emerging, positive self-efficacy seemed to co-occur with metacognitive awareness of content or language conventions. The study reveals the first-year doctoral students' miscalibration of self-efficacy for academic writing, posing a potential challenge for English for Academic Purposes (EAP) writing instructors to address in genrebased writing instruction. It also demonstrates the crucial role of mastery experience, vicarious experience, and emotional states in enhancing students' academic writing self-efficacy, suggesting the necessity of providing opportunities for students to achieve success in writing, observe peers, and obtain positive feedback in L2 genre-based writing classrooms.