Background The aim of this study was to compare the effectiveness of ultrasound-guided (USG) subcostal transversus abdominis plane (TAP) block and quadratus lumborum (QL) block as preventive analgesia methods after laparoscopic cholecystectomy. Methods A total of 120 patients, 18–75 years of age, were separated into 2 groups preoperatively. Patients in group TAP (n = 60) received 0.3 ml/kg bupivacaine with USG bilateral subcostal TAP block; patients in group QL (n = 60) received 0.3 ml/kg bupivacaine with USG bilateral QL block. Patients were assessed 24 h postoperatively, and pain scores, time to first analgesia requirement, total analgesia dose, and postoperative complications during the first 24 h were recorded. Results Fifty-three patients in group TAP and 54 in group QL were ultimately evaluated. No statistically significant difference was found in at rest and dynamic visual analog scale scores between the groups. There was also no statistically significant difference between the groups with regard to total analgesia consumption. Although the duration of anesthesia was significantly longer in group QL, no statistically significant difference was found in the duration of surgery between the groups (p < 0.05). Conclusions Results of this study demonstrated that USG subcostal TAP and QL blocks similarly reduced postoperative pain scores and analgesia consumption, with high patient satisfaction. However, subcostal TAP block could be considered preferable to QL block because it can be applied easily and in a shorter time.