Student self-assessment engages the students in purposeful reflection about what they are learning and how they are learning it. This study investigated the perceptions of students and teachers towards the students' self-assessment ability in two Singapore primary schools. A total of 75 students were taught how to use self-assessment. Eighteen students' self-assessments were randomly selected and compared with an independent panel of teachers' assessment. The results revealed both differences as well as similarities between the students' and teachers' perceptions of students' self-assessment ability. The findings and the implications for students are discussed in concluding the article.