Background: Peritonsillar infiltration of local anesthetics has efficient pain relief in children undergoing tonsillectomy. We hypothesize that lidocaine plus dexmedetomidine will potentiate the analgesic effect of each other rather than. Objectives: This study aimed to compare the analgesic effect of peritonsillar infiltration of lidocaine, dexmedetomidine, or lidocaine/dexmedetomidine on post-tonsillectomy pain. The primary outcome is the time of analgesia. The secondary outcomes are postoperative pain score, the effect of study medications on postoperative hemodynamic, and complications. Patients and Methods: Ninety patients were randomly allocated to three groups, 30 patients each. L group, patients received 2mg/kg lidocaine. D group, patients received 1 μg/kg of dexmedetomidine. LD group, patients received 1 μg/kg of dexmedetomidine plus 2 mg/kg lidocaine. Results: The time of the first analgesia request (h.) was longer in the LD group (13.70 ± 2.91) when compared with the L and D groups. Postoperative pain score was significantly lower in LD and D groups compared with the L group (P <0.05) On the other hand, there was a significantly lower median VAS score in the LD group when compared with the D group (P1 <0.05) Postoperative paracetamol consumption was significantly lower in LD group (0.55 ± 0.51 gm/24h) when compared with D and L groups (0.65 ± 0.59, 2.25 ± 0.44 gm/24h respectively). Conclusion: the use of lidocaine with dexmedetomidine is better than using each drug alone in decreasing post-tonsillectomy pain and increasing the time to first request for analgesia with no significant postoperative side effects.