Ulcer remains a public health problem associated with high incidence and mortality rate worldwide. Musa acuminata is widely available plant used in local management of many diseases including gastrointestinal disorders, constipation, piles, and hemorrhoids. The aim of this study was to evaluate the antioxidants and antiulcer activity of aqueous unripe fruits extract of Musa acuminata in indomethacin-induced ulcer in rats. The gastric ulcer was induced by intra-peritoneal injection of indomethacin (60 mg/kg, i.p.). Ulcer index and percentage ulcer inhibition was calculated using standard equations. The Lipid Peroxidation (Malondialdehyde) marker was determined using Thiobarbituric acid Reactive Substances (TBARS) method. The superoxide dismutase activity (SOD) and catalase (CAT) level was determined using standard ELISA kits. The antioxidant vitamins (Vit A, C, and E) were assayed by spectrophotometric technique. The extract (100 mg/kg, 200 mg/kg) demonstrated significant (p < 0.05) gastroprotective effect with high ulcer inhibition (95.49 %) at 200 mg/dL more than the reference standard drug, omeprazole (91.67 %). The extract (100 mg/kg, 200 mg/kg) demonstrated significant (p < 0.05) decrease in the level of lipid peroxidation marker (MDA) coupled with the significant (p < 0.05) increase in the level of SOD and CAT comparable to the reference standard drug, omeprazole. The results also showed a significant (p < 0.05) increase in vitamins A and E level significant (p < 0.05) decrease in vitamins C level in the gastric tissue homogenates of the rats treated with 100 mg/kg and 200 mg/kg of the extract. The aqueous unripe fruits extract of Musa acuminata demonstrated gastroprotective effect in indomethacin-induced ulcer in rats and might be attributed to increase in prostaglandins synthesis and cellular antioxidant activity.