This research study aimed to investigate how gender influences primary-aged children’s perceptions of mathematics attainment. A year 2 class and their teacher participated in interviews, questionnaires, document analysis, observations, and field notes. The research identified social perception, mathematics anxiety, task design and the role of the teacher as influential in forming children’s perceptions of attainment. Boys tended to have higher inferred self-perceptions of their attainment than girls of the same level, with girls being more likely to underestimate their attainment in mathematics. The research concludes by describing the examined relationship and encouraging teachers to address this difference in self-perceptions of attainment by gender in their planning and teaching of primary mathematics.