Quercetin content in Moringa oleifera has scientific potential antioxidant and anti-inflammation effects by inhibiting the activity of NF-ĸB. In addition, triterpenoids stimulate pancreatic β cell regeneration and increases insulin secretion. This study aimed to discover the effect of Moringa oleifera extract on insulitis and insulin expression in pancreas of Sprague-Dawley male rats. The study was performed at the laboratory of Food and Nutrition Unit of The Inter University Center of Gadjah Mada University and the laboratory of Histology and Cell Biology Faculty of Medicine Gadjah Mada University during May–July 2013. This was a randomized post test only controlled group study. Twenty four rats were included. Blood glucose test was performed on the third day after streptozotocin induction to ensure that all rats were in hyperglycemic condition. The rats were then divided into three groups: one control group and two treatment groups receiving Moringa oleifera ethanolic leaves extract for 21 days in doses of 250 and 500 mg/kg/day, respectively. Histopathological analysis of pancreas were performed by evaluating insulitis based on the infiltration of mononuclear inflammatory cells to the Langerhans islets. Insulin expression was evaluated using Allred score. Statistical analysis used was Kruskal-Wallis test, followed by Mann-Whitney with a level of significance of p<0.05. The insulitis degree and insulin expression of the two treatment groups were significantly different compared to the control group (p<0.005). It can be concluded that Moringa oleifera ethanolic leaf extract doses of 250 and 500 mg/kg/day cause higher insulin expression and lower insulitis degree than in the control group.