<p>This study investigates the self-assessment practices of 20 undergraduate Saudi students using a detailed rubric in an English writing course. At the core of the research is an exploration of students’ perceptions, attitudes, and experiences with self-assessment, emphasizing how they respond emotionally and cognitively to the process. The participants, health sciences undergraduates, were enrolled in their third semester and engaged in self-assessment before submitting their first essay. Data were collected using a rubric, questionnaire, and interviews, providing both survey results and qualitative insights into the use of a rubric to self-assess. The rubric addressed various criteria such as process, format, referencing, organization, cohesion, content, vocabulary, and grammar. The results indicated that one-third accurately predicted their grades. Qualitative feedback revealed that self-assessment heightened error detection, criteria fulfillment, and grade improvement. However, challenges included oversight of errors due to knowledge gaps, and perceptions of self-assessment being low value. Although limited by its small cohort and short duration, this study contributes to our understanding of self-assessment in writing courses and its role in fostering student engagement and improving learning outcomes. The findings suggest self-assessment's potential to enhance students' metacognitive skills and academic performance when integrated with structured guidance and external evaluations.</p>