Self-assessment is a beneficial practice in students' development of evaluative judgement. In order to enhance students' evaluative skills, a self-assessment treatment was introduced in the Economics Education I module at Samtse College of Education. The students are expected to self-assess various classroom activities and module assignments. For the students to be able to self-assess their learning, the researcher introduced specific instructional rubrics and gradation criteria to ensure quality and for students to carry out self-assessment. Using a mixed-methods design, the study examined the effects of self-assessment on students' evaluative skills. The data were collected using a one-group pre- and post-survey questionnaire followed by open-ended responses and document analysis. The participants were 17 economics students who were purposefully selected. The key findings reveal that self-assessment, if carried out rigorously and effectively, can enhance students' evaluative skills. The results also indicate that self-assessment action on developing students' evaluative skills was positive and statistically significant. The study suggests the importance of involving students in the design of tasks, rubrics, and assessment criteria for developing students' evaluative skills.