Non Steroidal Anti-inflammatory Drugs (NSAID) have been implicated in the etiology of gastritis. Mefenamic acid is a non-selective NSAID used to treat mild to moderate pain and inflammation. Mefenamic acid induces gastritis through its inhibition of prostaglandin that results in increased HCl secretion, decreased mucin, and bicarbonate ion production. This study aimed to investigate the gastroprotective effect of onion peel extract (OPE) against mefenamic acid-induced gastritis. In this study, the gastroprotective effect of OPE was examined through mucosal integrity scoring. A total of 28 male Wistar rats were divided into 4 groups, normal (Group 1), mefenamic acid+NaCMC 0,5% (Group 2), mefenamic acid+OPE 600mg/kg body weight (Group 3), and mefenamic acid+OPE 1200mg/kg body weight (Group 4). All rats were sacrificed on day 15 then all gasters were collected. Histopathological examination was done under a microscope with 100X magnification. Administration of mefenamic acid without OPE at all significantly increased gastric mucosal damage (p<0,05). Administration of OPE 1200mg/kg body weight significantly decreased gastric mucosal damage (p<0,05). Group 4 shows no significant difference (p=0,66) with the normal group (Group 1). This indicates that administration of OPE 1200mg/kg body weight per oral ameliorates mefenamic acid-induced gastritis.