Objective The effect of nutritional support on postoperative well-being and quality of life in gynecologic oncology patients was investigated. Material and methods Patients who underwent surgery for gynecologic oncologic reasons between August 2022 and December 2023 were included in the study. Those who received preoperative nutritional support were referred to as group 1 and those who did not were referred to as group 2. Demographic data, Quality of Life Form (EORTC QLQ-C30), Nutritional Risk Index score (NSR 2002), Hospital Anxiety and Depression Scale, surgical characteristics, and perioperative laboratory results were evaluated. Results A total of 215 patients were evaluated, 99 in group 1 and 116 in group 2. Group 1 was associated with shorter wound healing time (P = 0.020) and shorter hospital stay (P = 0.025), higher postoperative hemoglobulin (P = 0.001), higher ferritin (P = 0.001), lower CRP (P = 0.044), and albumin (P = 0.001), lower depression (P = 0.001) and anxiety (P = 0.001) and higher functional status and lower symptom scores than group 2 (P = 0.001). Conclusion Nutritional support in gynecologic oncology has a positive effect on postoperative well-being and quality of life, especially in patients with high Nutritional Risk Index.