Abstract: Tuberculosis continues to be a common health problem worldwide. Isoniazid, an antibiotic used routinely for tuberculosis chemotherapy is documented to be a potent hepatotoxicant. The aim of the present study was to assess the hepatoprotective activity of green tea (Camellia sinensis) extract (GTE) against isoniazid induced hepatotoxicity in the rats. Male Wistar rats were randomly allocated into 4 groups of 10 animals each including: normal healthy control rats, healthy rats receiving GTE, toxicant control and toxicant drug plus GTE treatment group. In groups 2 and 4 GTE (1.5%, w/v) was given as only source of drinking for 8 weeks. In the midst stage of experiment (4th and 5th weeks), Isonizid (50 mg kg^-1 b.w./day, i.p.) was administrated for groups 3 and 4 for a period of 2 weeks. At the end of experiment, serum biomarkers of liver tissue injury and product of lipid peroxidation (MDA), activities of Superoxide Dismutase (SOD), Catalase (CAT), Glutathione Peroxidase (GPX) and Glutathione Reductase (GR) were assayed in liver homogenates. Finally, the biochemical findings were matched with histopathological verifications. Significant differences among the groups were determined by one-way analysis of variance followed by Tukey post-test. In group 4, GTE significantly (p<0.05) decreased the elevated levels of serum biomarkers of hepatic injury and total bilirubin and significantly (p<0.05) increased the reduced levels of serum albumin and total proteins (respectively p = 0.001, p = 0.032). In this group, GTE significantly (p<0.05) decreased the lipid peroxidation and elevated the decreased values of hepatic antioxidants. Histopathologically, the changes were in the same direction with biochemical findings. This study showed that the hepatoprotective effect of GTE in isoniazid-induced oxidative damage may be related to its antioxidant and free radical scavenging activity.