Abstract Background: As the field of surgery continues to evolve, subspecialty training is fast becoming integral to surgical education. Presently, orthopaedic surgery residents have opportunities to subspecialise in different areas. Objectives: The aim of this study was to determine the factors affecting the choice of desired subspecialties amongst orthopaedic surgery residents in southern Nigeria. Materials and Methods: This study was a cross-sectional study conducted amongst senior orthopaedic surgery residents in southern Nigeria. A well-structured questionnaire designed using the free software Google Forms was electronically distributed to senior orthopaedic residents in Nigeria through online forums (WhatsApp, email, and Telegram). Data obtained were analysed using IBM Statistical Product and Service Solutions version 26. The odds ratio and the associated 95% confidence interval were used to assess outcomes, and a P value <0.05 defined that the difference was statistically significant. Results: At the end of the study period, 53 orthopaedic surgery senior residents completed and submitted the questionnaire with a response rate of 73.6%; 50.9% were married with children and 49.1% were single. The most agreed key factor influencing the choice of orthopaedic surgery subspecialisation from the study was lifestyle considerations (79.2%). Other major factors considered to be also very important were the needs of the region (73.6%), active mentorship (71.7%), ergonomics (64.6%), rotation experiences (47.2%), cost of acquiring the training (41.5%), and salary and financial privileges (37.7%). Overall, 24.5% of respondents chose spine surgery as their desired subspecialty, 18.9% arthroplasty, 17% arthroscopy, 17% paediatrics, 13.2% reconstructive orthopaedics, 5.7% musculoskeletal oncology, and 4.7% hand and foot surgery. Our study revealed a significant statistical relationship between having children and choice of a subspecialty (Fischer’s = 0.032; χ2 = 0.033), as the married female residents tend to have more family considerations in their final choice of subspecialisation. Conclusion: The choice of orthopaedic surgery subspecialisation amongst orthopaedic surgery residents in southern Nigeria is affected by different factors, such as mentorship, needs of region, desire to work in academic settings, and ergonomics.