Purpose <p>Quality of life (QoL) assessments in surgical practice have traditionally focused on postoperative recovery and long-term outcomes. This study evaluated the predictive value of preoperative QoL for postoperative complications.</p> Methods <p>We retrospectively analyzed the prospectively collected data from 908 patients who underwent gastrectomy for gastric carcinoma. Preoperative QoL was measured using the EORTC QLQ-C30 and STO22 questionnaires. A multivariate logistic regression was used to develop a predictive model, and model performance was assessed with a receiver operating characteristic (ROC) curve.</p> Results <p>Distal gastrectomy was performed in 763 patients (84.0%) and total gastrectomy in 145 patients (16.0%). Postoperative complications occurred in 189 patients (20.8%); local and systemic complications were observed in 160 (17.6%) and 48 (5.3%) patients, respectively, with some overlap. Patients with complications had significantly lower preoperative QoL scores across multiple functional and symptom domains. The predictive model identified global health status, stomach pain, anxiety, and body image as key indicators for complications, with an area under the ROC curve of 0.630 (95% CI 0.583–0.676). High-risk QoL classification by the model was an independent predictor of complications after adjusting for clinical risk factors.</p> Conclusion <p>Preoperative QoL, reflected in multiple functional and symptom domains, is associated with increased postoperative complications. Early identification of high-risk patients may facilitate targeted interventions to improve surgical outcomes.</p>