Background: Physical education (PE) aims to enhance self-esteem, develop sporting interests and to encourage a physically active life-style. However, little is known about how a fear of negative evaluation (FNE), the socially evaluative aspect of social anxiety, affects children's attitudes to PE. Aim: The aim of the study was to investigate the relationships between perceived athletic competence and FNE within PE lessons, specifically looking at differences between boys and girls and primary and secondary schools. Sample: The participants were 192 children in three primary schools (N = 85, mean age = 9.5 plus or minus 1.1 years) and two secondary schools (N = 107, mean age = 14.5 plus or minus 0.8 years) from rural areas of North Wales and the Midlands region of England. Methods: The participants completed the Brief-FNE Scale and the Self-Perception Profile for Children immediately post-lesson on one occasion. Results: Girls had higher FNE but lower perceptions of athletic competence than did boys. Older girls had higher FNE and lower perceived competence than the remaining three groups. Additionally, a significant and reverse but weak correlation was observed between girls' perceived athletic competence and FNE. Conclusions: The findings suggest that girls with a high FNE report lower perceptions of their athletic competence. Individuals who are high in FNE behave in ways to avoid the prospect of being evaluated negatively. However, they may seek feedback from significant others as a signal that unfavourable evaluations have been avoided. Therefore, positive, encouraging feedback used in child-centred learning strategies may foster feelings of competence in boys and girls and could reduce the girls' social anxiety.