Background <p>Nigeria faces a severe shortage of mental health specialists, with fewer than 300 psychiatrists serving a population exceeding 234&#xa0;million. Strengthening postgraduate psychiatric training is therefore critical, yet empirical evidence on the structure and implementation of residency programmes in Nigeria remains limited. This study aimed to systematically assess the structure and delivery of postgraduate psychiatric training across all accredited training centres in Nigeria, evaluate compliance with regulatory college standards, and identify actionable areas for improvement.</p> Methods <p>A cross-sectional descriptive online survey was conducted across all 30 institutions accredited for postgraduate psychiatric training by the National Postgraduate Medical College of Nigeria (NPMCN) and/or the West African College of Physicians (WACP) between June and July 2024. Heads of Department or designated trainers at each institution completed a researcher-developed, 35-item questionnaire via Google Forms. Twenty-nine institutions responded (response rate: 96.7%). Data were analysed using STATA version 17.0. Descriptive statistics summarised institutional characteristics and training practices. Responses to the open-ended question on Part II preparation strategies were analysed thematically.</p> Results <p>Among 109 health institutions in Nigeria accredited for postgraduate medical training in various specialities, only 30 (27.5%) offered postgraduate training in psychiatry. The median duration of accreditation was 20 years (IQR: 12–26 years), with median figures of 30 psychiatric beds, 7 consultant psychiatrists, and 11 resident doctors per institution. Core psychiatric rotations (General Psychiatry (100.0%), Addiction psychiatry (96.6%), Consultation-Liaison psychiatry (93.1%), Child and Adolescent psychiatry (93.1%), old age psychiatry (72.4%) and Psychotherapy (72.4%)) and preparations for Part I and Part II examinations were widely available. However, community psychiatry was limited to only 24.1% of training centres while 37.9% of centres lacked formal training manuals. Weekly journal clubs were conducted by 41.4% of centres while 44.8% of centres conducted monthly case conferences. Real-time end-of-posting assessments were conducted in only 34.5% of centres. Thematic analysis of Part II preparation strategies identified seven approaches, of which dissertation and research supervision (57.1%) and mock examinations and oral practice (53.6%) were most prevalent. A small number of institutions reported no formal Part II preparation programme.</p> Conclusion <p>Significant gaps exist in the distribution, capacity, and implementation of postgraduate psychiatric training across Nigeria, with marked variability in subspecialty exposure, academic activity, assessment practices, and research integration. Addressing these gaps will require deliberate policy reforms, expansion of accredited training centres, curriculum standardisation, and stronger regulatory oversight to build a psychiatric workforce capable of meeting Nigeria’s growing mental health needs.</p> Ethics registration <p>The study was approved by the Institutional Review Committee of the Kwara State University Teaching Hospital with approval protocol number KWASUTH/IRC/246/VOL.II/45.</p> Clinical trial number <p>Not applicable.</p>