The limited usage of doxorubicin in chemotherapy returns to its toxicity on different organs. Thyme oil has antioxidant, anti-inflammatory, and anticancer activities. This study aimed to investigate the alleviative effect of thyme oil on doxorubicin-induced hepatotoxicity in rats. Twenty adult female albino rats (Rattus norvegicus) were randomly divided into four groups (5 rats/group): control group, thyme group received orally 0.5 mL thyme oil/kg body weight once/week for 6 consecutive weeks, doxorubicin group received intraperitoneally 2 mg doxorubicin/kg body weight once/week for 6 consecutive weeks, and “doxorubicin+thyme" group received both doxorubicin and thyme oil once/week for 6 consecutive weeks. Alteration in the liver ultrastructure and changes in the activities of serum aminotransferases and antioxidant enzymes were estimated in the current study. Liver histology of doxorubicin-treated rats showed congested blood vessels, masses of inflammatory leucocytic infiltration, and cytoplasmic vacuolation, and pyknotic nuclei of the liver cells. Liver ultrastructure of doxorubicin-treated rats showed vacuolated and rarified cytoplasm, enlarged ruptured mitochondria, and large number of lysosomes. The rough endoplasmic reticulum lost most of its ribosomes, and its cisternae were unparalleled, as well as the nuclear envelope was mild tortuous. In addition, the aminotransferases (ALT and AST) activities and MDA level were increased significantly; while the antioxidant enzymes (SOD and CAT) activities were decreased significantly in the doxorubicin-treated animals compared with the control group. In the current study, thyme oil ameliorated most of the hepatotoxic effects of doxorubicin in rats. Therefore, thyme oil can be used as adjunct therapy to reduce doxorubicin toxicity.