Purpose <p>The Advanced Trauma Life Support (ATLS) course serves as a foundational educational experience for medical providers. Understanding how instructor characteristics influence student performance is essential for optimizing ATLS instruction and addressing instructor shortages globally. We analyzed data from our institution to evaluate how instructor type, specialty, practice setting, and experience impact student written exam performance.</p> Methods <p>We performed a two-year retrospective analysis of all ATLS participants at a single high-volume ATLS training center. Primary outcomes included cumulative and topic-specific written exam performance. Independent variables included instructor level (attending vs. trainee), instructor specialty and practice setting (academic surgeon, community surgeon, emergency medicine), and instructor teaching experience (number of courses taught). Standard statistical analysis was performed.</p> Results <p>Of 191 students, 48.2% (N = 92) were advanced practice providers and 51.8% (N = 99) were physicians. Emergency medicine (49.7%, N = 95) and general surgery (16.2%, N = 31) were the most common represented specialties. Exam topic performance was similar across all instructors. Identified exceptions included pediatric and airway topics, with pediatrics when taught by community general surgeons (98.6%) compared to academic surgeons (93.6%) or trainees (91.5%, <i>p</i> = 0.05) and airway when taught by community emergency physicians (98.6%) compared to academic surgeons (85.0%) or trainees (81.7%, <i>p</i> &lt; 0.001). On linear regression there were improved scores in initial assessment, airway, and spine when taught by more experienced instructors.</p> Conclusions <p>The ATLS course is the leading course available for learning management of complex trauma patients; thus, effective instructors are critical. While variations exist, resident educators were comparable to more experienced attendings, supporting the continued use of resident teaching roles in ATLS.</p>