Purpose: Surgery is a complex sociotechnical system where performance depends on the interaction of individual, technical, and organizational factors. This review compares factors contributing to cognitive load and the impact on technical precision and error rates of surgical trainees. Methods: A systematic review of qualitative studies between 2005-2024 examining human factors in an operating theatre environment were eligible for inclusion. Studies PubMed, Scopus and Embase databases were searched and abstracts screened for relevance. Thematic analysis was conducted via an inductive approach. Results: 22 studies were included in the review. 4 themes overarching themes, each with 3 subthemes were identified. 1. Multi-tasking with frequent switching between cognitive and manual tasks was a main contributor to technical error and increased operation duration. 2. Unfamiliarity of team members and frequent repeating of information in procedures with high complexity led to decreased situational awareness. 3. Physical effects of stress and fatigue, particularly in trainees, contributed to poor communication, reduced the quality of decision making, and slowed down manual dexterity. 4. New technology designed to improve efficiency is associated with initial increased cognitive demand, and increased disruption by additional personnel in theatre required to address these issues. Conclusion: Increased cognitive load is a primary driver of technical error. Managing mental demand through ergonomic theatre design, improving team familiarity, and standardising communication to reduce unnecessary disruptions may optimise technical precision and patient safety.