Purpose: The aim of the study explores the impact and potential mechanisms on the STZ (Streptozotocin)-induced diabetes model histopathologically and immunohistochemically on diabetic lung fibrosis. Materials and Methods: In this study, 14 adult female Wistar albino rats were divided into groups of seven random animals: the control and STZ induced diabetic groups. In the study, a blood glucose level above 200 mg/dl was accepted as diabetes. Nine days after the experiment, the rats were sacrificed under anesthesia and lung samples were taken from each. The histopathological appearance of the samples was evaluated and histopathologic damage score was performed. Apoptosis and inflammation in tissues were evaluated with caspase-3 and IL-1β immunohistochemically. Results: In the histopathological examination, the STZ group had a higher histopathologic damage score than the control group, and there were findings such as vascular congestion, thickened alveolar wall, and inflammatory cell infiltration. In the caspase-3 immunohistochemistry, staining of the lung tissues of the STZ group was higher than the control group. This difference was also significant in terms of IL-1β immunoreactivity intensity. Conclusion: This study determined that lung complications and damage due to diabetes-induced by STZ occurred.