Student academic self-assessment engages the students in deliberate reflection about what they are learning and how they are learning it. This intervention study investigated the effects of self-assessment training on students' perceptions towards self-assessment in two Singaporean primary schools. The study, which used a pretest-posttest design, involved 146 Primary 4 (aged 10) students with 75 students being taught the use of self-assessment (intervention group) and 71 students who did not receive any training (comparison group). Data was collected using a Self-Assessment Questionnaire, wherein the students reported on the domains of knowledge application, independent learning, communication and motivation. The results revealed an improvement in the intervention students' perceptions towards self-assessment after the use of self-assessment and there were differences between the intervention students and the comparison students. The findings and the implications for students will be discussed in the article.