Glucocorticoids are widely used in treatment of many medical disorders. However, many side effects are associated with the chronic use of glucocorticoids administration especially osteoporosis. Fish oil contains omega 3 polyunsaturated fatty acids which can inhibit the production of inflammatory mediators such as IL-6 and TNF-α which are important for osteoclastogenesis. So the aim of the present work was to test the efficiency of fish oil administration on alveolar bone osteoporosis induced by glucocorticoid administration. Materials & methods: 8 Wistar albino rats were divided into 3 groups. Group Ι: control group. Group ΙΙ (osteoporotic group): rats were given 7 mg/kg of dexamethasone, once a week intramuscularly for 5 weeks. Group ΙΙΙ (fish oil treated group): rats were given the same dose of dexamethasone like group ΙΙ and at the same time were given daily an oral dose of fish oil 1gm/kg/day. All rats were sacrificed after 5 weeks from the start of the experiment and molar segments of the jaw were dissected out. They were examined histologically, immunohistochemically, histomorphometrically and ultrastructurally. Results: Histologically in osteoporotic group ΙΙ the bone showed marked resorption with the presence of many osteoclasts which showed significant increase in number and intense TRAP immunostaining. By scanning electron microscope the buccal cortical plate showed obvious erosion. On the other hand, fish oil treated group showed marked improvement where the bone appeared denser with significant decrease in osteoclast number which exhibited mild TRAP staining. Histomorphometriclly, the bone surface area showed marked increase. Ultrastructurally, the bone surface appeared relatively smooth. Conclusions: fish oil supplementation could to a large extent overcome the detrimental effect of glucocorticoid administration on the structure of the alveolar bone.