OBJECTIVE: The purpose of this study is to evaluate the effect of resident participation on operative time and surgical complications in isolated lower extremity fracture care. SETTING: Patients who were treated at teaching hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program database. PARTICIPANTS: A total of 2,488 patients who underwent surgical fixation of isolated hip fractures, femoral or tibial shaft fractures, and ankle fractures. DESIGN: Patients were stratified by surgical procedure and post-graduate year (PGY) of the resident involved. Total operative time and surgical complications were analyzed with respect to resident participation and seniority. Multivariable logistic regression analyses were used to adjust for potential confounders including case complexity, wound class, and patient comorbidity burden. RESULTS: As PGY level increased, operative time increased for each procedure. The odds for a deep surgical site infection decreased as resident seniority increased, but the odds for wound dehiscence increased as resident seniority increased. We found no difference in the incidences of superficial infections or return to the OR with respect to PGY level. Academic quarter within the academic year did not correlate with any of the surgical complications. Furthermore, when cases performed with residents were compared to those performed without residents, there was no increased risk of superficial infections, deep infections, or return to the OR. CONCLUSIONS: This nationally representative dataset demonstrates that operative times for lower extremity orthopedic trauma increased as resident seniority increased. Additionally, senior resident participation was associated with increased wound dehiscence, whereas junior resident participation was associated with an increased risk of deep surgical site infections. However, there was no associated "July effect" for residents at any level of training and there was no increased risk for surgical site infections or return to the OR in cases involving resident participation.