Articulating ideas in writing based on English conventions may be one of the biggest challenges for English as a foreign language students, which makes corrective feedback (CF) an indispensable part in writing practice. In terms of providing CF, researchers have claimed that indirect CF has a number of advantages for the improvement of students' writing accuracy. However, it may also have a negative impact on students' writing accuracy through decreasing their writing motivation (Mohamed & Zouaoui, 2014). Few empirical studies have explored the potential role of motivation in students' writing accuracy. Multiple factors are related to student motivation, and affective teacher comments is one of such factors. In this sense, this quantitative study employed a quasi-experimental design to examine whether students' writing accuracy can be enhanced by the addition of affective teacher comments to indirect CF. A total of 231 EFL students participated in this 13-week study. Two-way factorial ANOVAs were conducted to investigate the effects of indirect CF (indirect coded CF or indirect non-coded CF) and affective teacher comments (affective teacher comments or no affective teacher comments) on the students' writing accuracy in new writings and revisions. For the factor of affective teacher comments, the results revealed that beginning with similar level of writing accuracy, the groups who were provided affective teacher comments significantly outperformed the groups who were not provided such comments in both new writings and revisions. However, for the factor of indirect CF and the interaction effect between the two factors, no such positive result was found. This study provides further evidence that individual differences, such as motivation, may have an impact on students' writing accuracy. Writing teachers can think of various ways (e.g., they can offer affective comments to praise on students' strengths in writing) to boost student motivation when providing CF on student writing. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]