Background. Transversus abdominis plane (TAP) block is used for postoperative analgesia in laparoscopic cholecystectomy. In laparoscopic cholecystectomy, the incisions are located mainly on the upper right side of the abdomen. Aims. We aim to determine the efficacy of less-invasive ultrasound-guided right unilateral oblique subcostal TAP block in laparoscopic cholecystectomy on postoperative analgesia by comparing patients undergoing bilateral TAP block and a control group. Methods. Ninety patients were equally divided into control, unilateral, and bilateral TAP block groups. TAP blocks were conducted before anesthesia. No block was applied to the control group. Patients’ demographics and postoperative pain, satisfaction, and nausea-vomiting scores and tramadol/ondansetron doses were evaluated. Results. There was no significant difference in the verbal numerical rating scale for pain scores at rest and during coughing (VNRS-R and VNRS-C) between unilateral and bilateral TAP block groups at postoperative 1 hour, 2 hour, 4 hour, 8 hour, 12 hour, and 24 hours. In addition, VNRS-R and VNRS-C scores were significantly higher in the control group than in the other two groups. Tramadol consumption in the control group was significantly higher than in the unilateral and bilateral TAP block groups
p
≤
0.01
, while no significant difference was identified between unilateral and bilateral TAP block groups
p
=
0.303
. Nausea-vomiting scores and ondansetron consumption did not differ significantly between all the groups. Patient satisfaction was significantly higher in unilateral and bilateral groups
p
<
0.01
,
p
<
0.01
than in the control group, while there was no significant difference between unilateral and bilateral TAP block groups
p
=
0.793
. Conclusions. Right unilateral TAP block provides postoperative analgesia as effective as bilateral TAP block in laparoscopic cholecystectomy.