Background: Surgical site infection (SSI) remains a significant and costly complication after trauma surgery, contributing to increased morbidity, prolonged hospitalization, and higher healthcare expenditures. Identifying the incidence and modifiable risk factors specific to the general trauma surgery population is essential for developing targeted prevention strategies. Methods: A single-center retrospective cohort study was conducted. We included 2,134 adult patients who underwent emergency general trauma surgery (e.g., laparotomy, thoracotomy, repair of major fractures with soft tissue involvement) between January 2018 and December 2022. SSI was defined and classified according to the Centers for Disease Control and Prevention (CDC) criteria. Patient demographics, injury characteristics, operative details, and perioperative management data were collected. Univariate analyses and multivariate logistic regression were performed to identify independent predictors of SSI. Results: The overall incidence of SSI was 9.2% (197/2134). Superficial incisional SSI accounted for 5.6%, deep incisional SSI for 2.5%, and organ/space SSI for 1.1%. Multivariate analysis identified six independent risk factors: open fracture (Gustilo type III) or gross intra-abdominal contamination at injury (adjusted odds ratio [aOR] 3.71, 95% confidence interval [CI] 2.54-5.42), surgery duration >180 minutes (aOR 2.95, 95% CI 2.05-4.25), requirement for massive transfusion (>10 units of packed red blood cells in 24 hours) (aOR 2.73, 95% CI 1.88-3.96), preoperative hypothermia (core temperature <36.0°C) (aOR 2.41, 95% CI 1.68-3.46), diabetes mellitus (aOR 2.02, 95% CI 1.39-2.93), and body mass index (BMI) ≥30 kg/m² (aOR 1.78, 95% CI 1.23-2.58). Appropriate preoperative antibiotic prophylaxis (administered within 60 minutes before incision) was a significant protective factor (aOR 0.38, 95% CI 0.26-0.56). Conclusion: SSI complicates nearly one in ten general trauma surgeries, with several strong and potentially modifiable risk factors. These findings underscore the importance of protocolized care bundles addressing timely antibiotic administration, normothermia maintenance, blood conservation strategies, and consideration of damage-control surgery in high-risk patients to reduce the burden of SSI.