Aim of the work- Diabetes mellitus is a common metabolic disease not only affecting the individual, but also imposes adverse effects on the offsprings. Besides increasing congenital malformations, maternal diabetes is suggested to be associated with early pregnancy loss, altered sex ratio in the offspring and long-term postnatal diseases. Antidiabetic plants are used as supportive therapy in the treatment of diabetes during pregnancy, so the present study aims to investigate the protective effect of olive leaf extract on the fetal lung of the diabetic pregnant rats. Material and methods - Forty pregnant albino rats were used and categorized after mating into four groups; group 1: control group(C), group 2: rats treated with olive leaf extract during the period of pregnancy (O) (1 ml/100gm. b. wt), group 3: streptozotocin induced diabetic rats (D)(STZ 35 mg/kg b.wt), group 4: diabetic rats treated with olive leaf extract (D+O) (as in groups 2&3). The pregnant females of different groups were dissected during the 19 ^th day of pregnancy. Lung samples of fetuses were taken for the histological and histochemical studies.  Results- Histopathological and histochemical observations of fetal lung tissue showed that the olive leaf extract succeeded to minimize the drastic changes which were observed in the fetal lung of diabetic rats. Conclusion- It is recommended that the use of the olive leaf extract has the ability to minimize the adverse effects in the fetal lung tissue of diabetic rats.