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 posttonsillectomy pain and increasing the time to first request for analgesia with no significant postoperative side effects.