Background The educational environment impacts on various aspects of students’ professional development and well-being and is an important aspect of medical education programmes. Limited research investigating the theatre educational environment has been identified in South Africa and there is limited understanding of this environment at the University of the Witwatersrand (Wits). This study aims to describe the educational environment in theatre for registrars in the Department of Anaesthesiology at Wits. Methods A prospective, descriptive study design was followed, involving anaesthetic registrars at Wits, using the adapted Anaesthetic Theatre Educational Environment Measure (ATEEM) questionnaire between April and June 2019. A convenience sampling method was implemented to administer the anonymous questionnaire. Categorical variables were described using numbers and percentages. Descriptive statistics were used to calculate the total scores. The independent t-test or analysis of variance test was used to make comparisons. Results A total of 85 anaesthetic registrars participated in this study. The mean total (SD) adapted ATEEM score was 116.5 (16.9) out of a total of 164. The total score for male and female registrars was 118.4 (13.5) and 115.3 (18.7) respectively (p=0.419). First-year registrars scored 121.6 (14.3), second years 111.1 (19.0), third years 111.4 (14.6) and fourth years 122.3 (18.7) (p=0.003). Junior and senior registrars scored 117.1 (17.0) and 115.7 (17.1) respectively (p=0.708). The three hospitals were scored 112.3 (19.5), 119.8 (16.4) and 115.4 (12.0) respectively (p=0.187). The mean scores for the five domains were autonomy 25.4/32 (3.1), perception of atmosphere 31.6/44 (5.4), workload/supervision/support 17.3/28 (3.5), perception of teachers and teaching 14.3/20 (2.9), and learning opportunities and orientation to learning 27.9/40 (5.1). Conclusion The theatre educational environment is perceived as more positive than negative, but with room for improvement. The specific domains that require attention to further improve the educational environment were perception of atmosphere, workload/supervision/support, perception of teachers and teaching, and learning opportunities and orientation to learning. With the availability of a validated instrument to assess the educational environment objectively and quantitatively, regular quality assessments of the educational environment should be included in the training institution’s practice.