Previous studies have suggested a postoperative "catch-up growth" in children undergoing tonsillectomy. Given the tonsils' crucial role in early immune development, examining long-term effects is imperative. This study aims to investigate the impact of tonsillectomy in early life on adult height and height disparity.Using data from the UK Biobank, we compared individuals with a childhood tonsillectomy to individuals without such an experience, after matching them individually by age and sex. We used standing height measured at recruitment to the UK Biobank as attained adult height, polygenic risk score (PRS) for height as a proxy for genetically determined height, and height deviation and height deficit as proxies for height disparity. We assessed the association of tonsillectomy with these outcomes, using a linear mixed-effect model or conditional logistic regression, after multivariable adjustment.Individuals with a childhood tonsillectomy had a slightly higher attained adult height (mean: 169.0 cm; standard deviation [SD] 9.23) compared to their age- and sex-matched comparators (mean: 168.5 cm; SD 9.30). After multivariable adjustment, childhood tonsillectomy was associated with a marginally higher attained adult height (β: 0.34; 95% confidence interval [CI]: 0.26-0.41), a positive height deviation (β: 1.7; 95% CI: 1.4-2.1), and lower odds of height deficit (odds ratio [OR]: 0.89; 95% CI: 0.87-0.92), but not PRS for height (β: -0.24; 95% CI: -0.50 to 0.03). The first three associations were more pronounced among individuals with a lower PRS for height, compared to those with a higher PRS for height. The magnitude of the associations for adult height and height deviation also appeared to decrease with increasing age at surgery.Individuals with childhood tonsillectomy did not demonstrate height disparity as adults, compared to individuals without such a procedure or relative to their genetically determined height.3.© 2025 The Author(s). Laryngoscope Investigative Otolaryngology published by Wiley Periodicals LLC on behalf of The Triological Society.