Early surgical intervention to decompress the spinal cord and stabilize the spinal column in patients with acute traumatic thoracolumbar spinal cord injury (TLSCI) may lessen the risk of developing complications and improve outcomes. However, there has yet to be agreement on what constitutes "early" surgery; reported thresholds range from 8 to 72 h. To address this knowledge gap, we conducted an observational cohort study using data from the American College of Surgeons (ACS) Trauma Quality Improvement Program (TQIP) from 2010 to 2016. The association between time from hospital arrival to surgical intervention and risk of major complications was assessed using restricted cubic splines. Propensity score matching was then used to assess the association between delayed surgery and risk of complications. Across 354 trauma centers 4108 adult TLSCI patients who underwent surgery were included. Median time-to-surgery was 18.8 h (interquartile range [IQR]: 7.4-40.9 h). The spline model suggests the risk of major complication rises consistently after a 12-h surgical wait-time. After propensity score matching, the odds of major complication were significantly lower for those receiving surgery within 12 h (odds ratio [OR] 0.77, 95% confidence interval [CI]: 0.64 to 0.94). This was also true for immobility-related complications (OR 0.79, 95% CI: 0.64 to 0.97). Patients in the early group spent 1.5 fewer days in the critical care unit on average (95% CI: -2.09 to -0.88). Although surgery within 12 h may not always be feasible, these data suggest that whenever possible surgeons should strive to reduce the amount of time between hospital arrival and surgical intervention, and health care systems should support this endeavor.