This cross-sectional study investigates the factors influencing writing self-efficacy among EFL postgraduate students in Indonesia. It employs a quantitative analysis facilitated through partial least squares-structural equation modeling (PLS-SEM). The study engaged 150 master's and doctoral EFL students as participants, examining the variables of writing enjoyment, research literacy, and teacher clarity and teacher immediacy in feedback, in relation to writing self-efficacy. The findings revealed that research literacy significantly improves writing self-efficacy, particularly among doctoral students. This demonstrates the crucial role of research literacy in building students' confidence in their writing abilities. Furthermore, writing enjoyment was found to be a key factor in enhancing writing self-efficacy, especially for master's students. This pinpoints the necessity to nurture joy in the writing process. Teacher clarity was found to be essential for enhancing research literacy, whereas teacher immediacy had a lesser impact. This suggests a reduced reliance on teacher guidance during postgraduate studies. The study highlights the critical roles of research literacy and enjoyment in developing writing self-efficacy and illuminates the nuanced role of pedagogical strategies. These insights are valuable for educational institutions and policy-makers in strengthening the EFL postgraduate learning environment. The differences observed between master's and doctoral students call for further research to develop educational practices tailored to the different needs of these academic stages.