Students are the central agent in self-assessment; therefore, their perceptions are crucial for successful self-assessment. Despite the increasing number of empirical studies exploring how students perceive self-assessment, systematic reviews synthesising students' perceptions of self-assessment and relating them to self-assessment implementation are scarce. This review covered 44 eligible studies and synthesised findings related to two key aspects of students' perceptions of self-assessment: (1) usefulness of self-assessment; and (2) factors influencing their implementation of self-assessment. The results revealed inconclusive findings regarding students' perceived usefulness of self-assessment. Although most studies reported a generally positive perception of self-assessment among students, some studies revealed students' skepticism about its usefulness. Usefulness was influenced by specific individual factors (i.e., gender, age, and educational level) and instructional factors (i.e., external feedback, use of instruments, and self-assessment purpose). Additionally, implementation was influenced by specific individual factors (i.e., perceived usefulness, affective attitude, self-efficacy, important others, and psychological safety) and instructional factors (i.e., practice and training, external feedback, use of instruments, and environmental support). The findings of this review contribute to a better understanding of students' perceptions of self-assessment and shed light on the design and implementation of meaningful self-assessment activities that cater to students' learning needs.