Background: We aimed to investigate the effects of the external oblique intercostal plane block (EOIPB) and subcostal transversus abdominis plane (TAP) block on postoperative pulmonary function in patients undergoing laparoscopic cholecystectomy. The primary outcome was spirometric pulmonary function test (PFT) results. Secondary outcomes included postoperative pain scores, opioid consumption, and postoperative recovery assessed using the Quality of Recovery (QoR)-15 questionnaire. Methods: A total of 102 patients aged 18-65 years with ASA physical status I-III who underwent elective laparoscopic cholecystectomy were included in this prospective observational study. According to the perioperative analgesia technique applied, patients were evaluated in three groups: Group Subcostal (n=34), Group EOIPB (n=34), and Group Control (n=34). After losses to follow-up, 90 patients were included in the final analysis. Preoperative and postoperative spirometric PFTs, postoperative pain scores, opioid consumption, and QoR-15 scores were recorded and compared among groups. Results: Postoperative reductions in FVC, FEV1, predicted FEV1, and PEF values were observed in all groups but were significantly more pronounced in the Control group. At postoperative hour 1, pulmonary function parameters were significantly lower in the Control group compared with both block groups (p < 0.05). Predicted FEV1 at postoperative hour 1 was significantly higher in the EOIPB group than in Subcostal group (p = 0.003). Postoperative pain scores and opioid consumption were significantly lower in both block groups compared with the Control group (p < 0.05), whereas QoR-15 scores were significantly higher (p < 0.05). No significant differences were observed between the two block groups for most postoperative outcomes. Conclusion: Both EOIPB and subcostal TAP block were associated with attenuated decline in postoperative pulmonary function, reduced opioid consumption, and improved early postoperative recovery after laparoscopic cholecystectomy.