Tamoxifen citrate (TAM) is a widely used drug in breast cancer treatment. It showed a degree of hepatic carcinogenesis. The purpose of this study was to elucidate the antioxidant capacity of Moringa oleifera aqueous extract (MAE) against TAM-induced liver injury. A model of liver injury in male rats was done by orally administration of TAM in a dose of 3mg/Kg/3days for consecutive six weeks to evaluate the drug-toxicity in combination with MAE in a dose of 300mg/Kg/day for similar period. The model of TAM-intoxication elicited significant elevation in serum alanine aminotransferase (ALAT) and aspartate aminotransferase (ASAT) activities as well as hepatic levels of the oxidative stress markers (MDA and NO),lipid profiles and inflammatory marker(TNF-α) associated with a significant depletion of anti-oxidative marker (GSH).The oral administration of MAE in combination with TAM-intoxicated rats, resulted in significant improvements in ALAT,ASAT and anti-oxidative marker (GSH)with significant decrements in MDA, NO and lipid profiles. The data obtained from this study speculated that MAE has the capacity to scavenge free radical and can protect against oxidative stress induced by TAM intoxication. Supplementation of MAE could be useful in alleviating tamoxifen-induced liver injury in rats.