Background: Radiation-induced lung injury is a common complication after esophageal, breast, etc. cancer radiotherapy. We aimed to evaluate the radioprotective effect of arbutin on acute radiation-induced lung damage in male rats. Materials and Methods: Fifty-two male Wistar rats were divided into 4 groups: (i) control group (n = 10), (ii) vehicle group (n = 10, received distilled water intraperitoneally (ip)), (iii) X-irradiation only (n=16, chest was irradiated to a single dose of 20 Gy x-rays) and (iv) arbutin + X-irradiation (n=16, 75 mg/kg of arbutin 2 hours before irradiation (ip), and then their chest was exposed to 20 Gy x-rays). For histopathological investigation, 8 animals of each group were sacrificed 8 weeks after treatment and the rest of them were sacrificed 3 months after treatment. Results: The histopathological analysis in 8 weeks after X-irradiation showed that there was a significant increase in inflammatory in X-irradiation only group compared to control group. The administration of arbutin 2 hours prior to X-irradiation significantly reduced inflammation and inflammatory factors such as macrophages, mast cell and neutrophil in arbutin + X-irradiation group compared to X-irradiation only group (P<0.05). The histopathologic investigation performed 3 months after lung irradiation indicated a significant reduction in fibrosis formation in arbutin + X-irradiation group compared to irradiation only group (P<0.05). Localized chest X-irradiation with 20 Gy caused histopathologic damage to the lungs for short -term. Conclusion: Arbutin has a great potential in reducing the histopathologic damage to lung tissue after thoracic irradiation.