Objective: To compare the postoperative analgesic duration of intrathecal Dexmedetomidine versus Buprenorphine as an adjuvant to 0.5% heavy Bupivacaine in spinal anesthesia for orthopedic surgeries at a tertiary care hospital. Methodology: An RCT was conducted in the Orthopedics Operation Theaters Department of Anesthesiology at Nishtar Hospital Multan from October 15, 2022, to April 14, 2023. Groups A and B were randomly assigned to sixty patients who were set to have Orthopaedic surgery. Intrathecal five micrograms of dexmedetomidine and 15mg of 0.5% strong bupivacaine were administered to participants in Group A (per hospital protocols). The doses of buprenorphine and 0.5 percent strong bupivacaine given to Group B were 60µg and 15mg, respectively. The length of postoperative analgesia was the primary outcome. Results: The mean age of the study population was 33.45 ± 6.83. Out of these 60 patients, 41 (63.33%) were males. The mean BMI was 28.47 ± 3.12 kg/m2. The frequency of patients in the ASA I group was 34 (56.67%). The mean duration of analgesia in the intrathecal Dexmedetomidine group was 494.90 ± 38.46 minutes, compared with 283.03 ± 17.97 minutes in the buprenorphine group (p-value<0.05). Post-stratification analysis regarding age groups, gender, BMI, type of surgery, obesity, and residential status also showed significant results. Conclusion: Results showed that intrathecal Buprenorphine had a shorter duration of postoperative analgesia than spinal anesthesia with dexmedetomidine adjuvant to bupivacaine.