Introduction: Multiple studies have been shown neuroprotective effect of Gallic acid (GA) as a potent anti-oxidant substance. Furthermore, trimethyltin (TMT) is a methylated organotin compound which induces neuronal degeneration in the brain of human and rodents. This study examined the effects of GA on wet weight of the cerebellum, cerebellum to total brain weight ratio, and purkinje cells number in lobule IV, V, and VI in the brain of TMT-intoxicated rats. Materials and Methods: Fifty adult male sprague dawley rats were divided into five groups; control, TMT+Saline group received saline after TMT (8 mg/Kg/BW) intoxication as well as TMT+GA50, TMT+GA100 and TMT+GA200 groups. Animals received GA 50, 100 and 200 mg/Kg body weight seven days before and seven days after administration of TMT. Finally, through transcardialy perfusion, the rats were sacrificed and the weight of total brain and cerebellum was measured and then histopathological analyses were conducted. Results: The wet weight of cerebellum were significantly decreased in TMT+Saline group compared to controls and increased in GA-treated rats compared to TMT+Saline group. However, the average cerebellar to total brain weight ratio was not differed in different groups. The number of Purkinje cells in the specific folia was significantly increased in the GA-treated rats in comparison to that of the TMT+Saline group. Conclusion: Our data indicate that GA reduced TMT toxicity and associated cerebellar damages possibly via its antioxidant and neuroprotective properties.