Aims. The aims of this study were to describe the demographic, socioeconomic, and educational factors associated with core surgical trainees (CSTs) who apply to and receive offers for higher surgical training (ST3) posts in Trauma & Orthopaedics (T&O). Methods. Data collected by the UK Medical Education Database (UKMED) between 1 January 2014 and 31 December 2019 were used in this retrospective longitudinal cohort study comprising 1,960 CSTs eligible for ST3. The primary outcome measures were whether CSTs applied for a T&O ST3 post and if they were subsequently offered a post. A directed acyclic graph was used for detecting confounders and adjusting logistic regression models to calculate odds ratios (ORs), which assessed the association between the primary outcomes and relevant exposures of interest, including: age, sex, ethnicity, parental socioeconomic status (SES), domiciliary status, category of medical school, Situational Judgement Test (SJT) scores at medical school, and success in postgraduate examinations. This study followed STROBE guidelines. Results. Compared to the overall cohort of CSTs, females were significantly less likely to apply to T&O (OR 0.37, 95% CI 0.30 to 0.46; n = 155/720 female vs n = 535/1,240 male; p < 0.001). CSTs who were not UK-domiciled prior to university were nearly twice as likely to apply to T&O (OR 1.99, 95% CI 1.39 to 2.85; n = 50/205 vs not UK-domiciled vs n = 585/1,580 UK-domiciled; p < 0.001). Age, ethnicity, SES, and medical school category were not associated with applying to T&O. Applicants who identified as ‘black and minority ethnic’ (BME) were significantly less likely to be offered a T&O ST3 post (OR 0.70, 95% CI 0.51 to 0.97; n = 165/265 BME vs n = 265/385 white; p = 0.034). Differences in age, sex, SES, medical school category, and SJT scores were not significantly associated with being offered a T&O ST3 post. Conclusion. There is an evident disparity in sex between T&O applicants and an ethnic disparity between those who receive offers on their first attempt. Further high-quality, prospective research in the post-COVID-19 pandemic period is needed to improve equality, diversity, and inclusion in T&O training. Cite this article: Bone Jt Open 2024;5(8):697–707