It has been a consensus that growth mindsets, self-efficacy, and metacognition have played their respective roles in academic writing. However, very few previous studies have investigated the contributions of those variables all together in single studies. Thus, the present study aimed to examine the interplay among academic writing growth mindsets, self-efficacy, and metacognition concomitantly as a single study by formulating seven hypotheses. Using partial least squares structural equation modelling (PLS-SEM), this quantitative study conveniently involved 464 undergraduate students from several majors, working with undergraduate theses. They were the students from four state universities and two private universities in Central Java and Papua, Indonesia. A valid and reliable questionnaire negotiating academic writing growth mindsets, self-efficacy, and metacognition was copied into the Google form, and the links were distributed to the respondents. Results demonstrated that, in the academic writing context, positive and significant relationships were encountered between growth mindsets and ideation selfefficacy, growth mindsets and convention self-efficacy, growth mindsets and selfregulation self-efficacy, ideation self-efficacy and convention self-efficacy, ideation self-efficacy and self-regulation self-efficacy, convention self-efficacy and self-regulation self-efficacy, and self-regulation self-efficacy and metacognition. Self-regulation self-efficacy mediated the correlation between growth mindsets and metacognition. Future's studies are expected to develop a structural model of academic writing factors by incorporating the other influential variable, e.g. critical thinking skills, because it might contribute to differences in academic writing skills.