Background: Preoperative pulmonary function plays a critical role in determining perioperative risk and postoperative recovery, particularly in patients undergoing major surgical procedures. Impaired lung function is associated with increased susceptibility to postoperative pulmonary complications (PPCs), prolonged hospital stay, and higher morbidity. Objectives: To evaluate the impact of preoperative pulmonary function parameters on surgical outcomes and to determine their predictive value for postoperative complications. Methods: This prospective observational study included 120 patients undergoing elective surgeries. Preoperative pulmonary function tests (PFTs), including forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), and FEV₁/FVC ratio, were recorded. Patients were stratified into normal and impaired pulmonary function groups. Postoperative outcomes such as incidence of PPCs, duration of hospital stay, need for intensive care, and mortality were assessed and compared. Results: Out of 120 patients, 72 (60%) had normal pulmonary function, while 48 (40%) showed impairment. PPCs were observed in 30 patients (25%). The incidence of complications was significantly higher in the impaired group (20/48; 41.7%) compared to the normal group (10/72; 13.9%). Mean hospital stay was longer in patients with impaired PFTs (9.2 ± 2.8 days) than those with normal function (6.1 ± 1.9 days). ICU admission was required in 18 patients (15%), predominantly in the impaired group (12/48; 25%). Reduced FEV₁ (<70% predicted) showed a strong association with PPCs (p < 0.01). Mortality was low (3.3%), with higher occurrence in patients with severe pulmonary impairment. Conclusion: Preoperative pulmonary function is a significant predictor of postoperative outcomes. Patients with impaired PFTs are at increased risk of complications and prolonged recovery. Routine preoperative pulmonary assessment can aid in risk stratification and optimization of perioperative care.