Purpose: The Geriatric Trauma Outcome Score (GTOS) has been developed and indicate to be a valid prognostic tool for the prediction of mortality in geriatric trauma patients (GTPs) during hospitalization. However, the predictive value of the GTOS for morbidity is still unclear. We aimed to evaluate the association between GTOS, morbidity and mortality in GTPs. Patients and Methods: We performed a retrospective cohort study between June 1, 2016, and May 31, 2020, and collected data for patients aged 65 years or older. These patients were treated at the Trauma Center of Tongji Hospital, Wuhan, China. Clinical data were retrieved from the trauma registry. The GTOS was calculated with the following formula: age + ISS * 2.5 + 22 (if any packed red blood cells were transfused within 24 hours after admission). The outcomes were mortality, morbidity, length of hospital stay (LOS), and functional outcome at discharge. Results: A total of 485 patients were enrolled: 214 (44.1%) were classified into the low-GTOS group, and 271 (55.9%) were classified into the high-GTOS group. The median (IQR) age was 68 (66-71) years; 361 (74.4%) were male. The most common mechanism of injury was vehicle collision (66.4%), followed by falls <2 m (19.6%). The median (IQR) ISS was 18 (14-22). The median (IQR) GCS was 13 (9-15). A high GTOS was associated with high rates of all-cause mortality (13.3% vs 0.9%, P < 0.001), complications (88.2% vs 31.8%, P < 0.001), unplanned intubation (19.2% vs 1.4%, P < 0.001), and unplanned admissions to the intensive care unit (8.5% vs 0.5%, P < 0.001). In multivariable logistic regression analysis, GTOS was associated with morbidity (OR 1.07, 95% CI, 1.05-1.09, p < 0.001) and mortality (OR 1.04, 95% CI, 1.02-1.06, p < 0.001). Conclusion: The GTOS is an independent predictor of morbidity and mortality in GTPs, and it will help us identify patients at high risk on admission.