Objective: This study explored the association between history of orthodontic treatment and changes in self-esteem among British adolescents. Design: Birth cohort study. Setting: United Kingdom. Participants: Data from 2600 participants of the British Cohort Study were analysed. Methods: Participants completed the Lawrence Self-Esteem Questionnaire (LAWSEQ) at the ages of 10 and 16 years. The change in LAWSEQ score over six years was the outcome. Participants were divided into two groups according to parental reports of orthodontic treatment at the same ages. The association between history of orthodontic treatment and six-year changes in LAWSEQ score was tested in linear regression models adjusting for demographic factors (adolescents’ sex and ethnicity), family socioeconomic status (parental social class and mothers’ education), perceived orthodontic treatment need and baseline LAWSEQ score. Results: According to parental reports, 8% of participants had a history of orthodontic treatment. The mean LAWSEQ score at baseline was 13.7 (95% confidence interval [CI] 13.6–13.9) and increased significantly over time by 1.7 units (95% CI 1.5–1.9). Orthodontic treatment history was positively, albeit not significantly, associated with change in LAWSEQ score (coefficient: 0.08, 95% CI –0.56 to 0.72). The direction of the association reversed but remained non-significant after adjustment for all confounders (coefficient: –0.19; 95% CI –0.68 to 0.30). Improvements in self-esteem were positively associated with mothers’ education (coefficient: 0.85; 95% CI 0.09–1.61) and negatively associated with self-esteem at baseline (coefficient –0.79; 95% CI –0.82 to –0.75). Conclusion: This six-year longitudinal study provided no evidence for an association between history of orthodontic treatment and changes in self-esteem during adolescence.