Gastric ulcer (GU) is a severe gastrointestinal illness. The incidence and prevalence of GU are increasing globally. This work aimed to evaluate the potential gastro-protective effects of olive leaves extract (OLE), a natural antioxidant, in experimental rats of gastric mucosal damage induced by indomethacin (IND). The rats (n=40) were assigned into 4 groups including: control, ulcer (IND), and two protective OLE groups at two doses of low 300 and high 450 mg/kg b.wt (OLE 300 mg + IND and OLE 450 mg +IND). Each dose of OLE was orally given daily for 14 days. Then, the rats were sacrificed 4 h post IND given. The blood samples and gastric tissues were collected for biochemical analysis, calculation of ulcer index and histopathological examination. The results showed that OLE pretreatment and pre-induction of ulcer decline ulceration of gastric preserved the normal structure of gastric mucosa. There were significant decline in ulcer index, and total gastric acidity with significant increase of gastric pH level compared with IND group. The pretreatment with OLE significantly decreased the gastric tissue oxidative stress (thiobarbituric acid reacting substances (TBARS)) and serum pro-inflammatory cytokines, with a significant elevation in gastric antioxidant enzymes activities compared with IND ingested rats. The high dose of OLE (450 mg/kg) showed a better protective capacity compared with the low dose of OLE (300 mg/kg). The results showed that OLE had a potent gastroprotective activity on IND induced GU, which could be explained by its effect as an anti-inflammatory and antioxidant agent.