Background: The long-term consequences of in-hospital complications remain largely unknown. We sought to study the effect of complications on the long-term functional outcome of trauma patients. Methods: Patients with an Injury Severity Score ≥ 9 admitted to 3, level I trauma centers between 2015 and 2017 were contacted 6 to 12 months postinjury and administered a validated trauma quality-of-life survey, assessing for the presence of any functional limitation. Functional limitation was defined as the inability to perform independently one or more activities of daily living (eg, driving, walking on flat surfaces/upstairs, dressing). Medical records and the trauma registry were reviewed systematically for all patient and injury variables. The occurrence of predefined in-hospital complications (eg, pneumonia, surgical site infection) was recorded. The impact of in-hospital complications on functional limitation was assessed using multivariate logistic regression models. Results: Of 1,709 patients, 1,022 completed the study. The mean age was 58 y, 56% were male, 94% had blunt trauma, and the mean Injury Severity Score was 15. A total of 168 patients (16.4%) had a minimum of 1 in-hospital complication and reported significantly more functional limitations in most activities of daily living at 6 to 12 months, compared with those without complications. In multivariable analyses adjusting for confounders, the occurrence of complications was associated with a greater likelihood of functional limitation 6 to 12 months postinjury (odds ratio = 1.82, 95% confidence interval 1.22–2.69, P = .003). Conclusion: Trauma patients with in-hospital complications have a worse long-term functional outcome. In addition to prevention of primary complications, more rehabilitation resources should be made available to trauma patients who survive complications.