Diabetes mellitus (DM) is a prevalent metabolic disorder that is associated with development of some complications in male reproductive system including testicular damage, sexual dysfunction, abnormal spermatogenesis, and infertility. Diosgenin is a natural steroidal saponin with anti-diabetic, anti-oxidative, and anti-inflammatory effects. This research study was undertaken to explore the protective effect of diosgenin against diabetes-induced testicular damage in the rat. Ten days following streptozotocin (STZ; i.p.), diosgenin was daily administered for 6 weeks (p.o.). Diosgenin administration to diabetic rats significantly improved body weight and lowered serum glucose. In addition, diosgenin-treated diabetic group had a significantly lower level of malondialdehyde (MDA), protein carbonyl, greater level of glutathione (GSH), and higher activity of superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) in addition to testicular improvement of ferric reducing antioxidant power (FRAP). Furthermore, diosgenin significantly improved serum insulin and testosterone level and alleviated testicular markers of inflammation including tumor necrosis factor α (TNFα) and interleukin 6 (IL-6) in diabetic rats. Moreover, apoptotic markers including caspase 3 activity, Annexin V, and DNA fragmentation decreased, mitochondrial membrane potential (MMP) accentuated, and myeloperoxidase (MPO) activity as a biomarker of neutrophil infiltration decreased in diosgenin-treated diabetic group. Additionally, diosgenin was capable to improve sperm count, motility, and viability in addition to prevention of damage to seminiferous tubules in diabetic animals. Collectively, diosgenin ameliorates testicular damage in DM, at least via partial suppression of apoptosis, oxidative stress, inflammation, and neutrophil infiltration and also via partial restoration of mitochondrial integrity.