Background: Post-laparoscopic shoulder tip pain (PLSTP) is a common, distressing complication attributable to diaphragmatic irritation by residual carbon dioxide following pneumoperitoneum. Intraperitoneal instillation of local anaesthetic agents has been proposed as a simple intervention to mitigate this pain, yet evidence on the optimal agent, concentration, and timing remains inconclusive. Objectives: To evaluate the effect of intraoperative intraperitoneal bupivacaine instillation on PLSTP by Visual Analogue Scale (VAS) score, analgesic requirement, and hospital discharge time following laparoscopic cholecystectomy. Methods: A prospective, randomised controlled trial was conducted at the Department of General Surgery, Government Stanley Medical College, Chennai, between November 2022 and December 2024. Seventy patients undergoing elective laparoscopic cholecystectomy for primary cholelithiasis were randomised to two equal groups: Group A (n = 35) received 50 ml of 0.25% bupivacaine instilled intraperitoneally over the diaphragmatic surface following cholecystectomy, and Group B (n = 35) served as untreated controls. The primary outcome was shoulder tip pain VAS score at 6 hours, and on postoperative days 1, 3, and 5. Secondary outcomes included analgesic consumption and time to discharge. Results: Both groups were comparable for age, sex, and comorbidities at baseline. Group A demonstrated significantly lower VAS scores at 6 hours (3.63 ± 1.22 vs 6.43 ± 1.80; p < 0.001), day 1 (3.03 ± 0.95 vs 5.51 ± 1.48; p < 0.001), and day 3 (2.40 ± 0.65 vs 3.69 ± 0.99; p < 0.001). No statistically significant difference was observed on day 5 (p = 0.073). A significantly greater proportion of Group A patients achieved same-day discharge (71.4% vs 11.4%; p < 0.001). Analgesic requirement showed a consistent but statistically non-significant reduction in Group A from day 1 onward. Conclusion: Intraperitoneal instillation of bupivacaine following laparoscopic cholecystectomy significantly reduces post-operative shoulder tip pain and facilitates early hospital discharge. This safe, simple, and cost-effective adjunct should be considered as a routine practice in laparoscopic cholecystectomy