Monosodium glutamate (MSG) is a commonly used flavor enhancer that may contribute to male infertility. Sodium selenite is inorganic chemical form of selenium (Se). Se is best known as an antioxidant. This study was designed to investigate the possible ameliorating role of sodium selenite against MSG-induced testicular toxicity and histological changes. Forty male albino rats were allocated into four groups. Control group received distilled water, SE group received sodium selenite (0.25 mg/kg/day) dissolved in distilled water orally, MSG group received MSG (6 mg/g/day) dissolved in distilled water orally, and MSG + SE group received both MSG and sodium selenite for 45 days. Testicular samples were prepared for biochemical, light, and electron microscopic studies. Immunohistochemical staining for caspase-3 was done. MSG group demonstrated a significant increase in malondialdehyde level, marked damage of seminiferous tubules with a significant reduction in diameter and height of the lining epithelium. Spermatogenic cells showed disorganization, dark nuclei, reduction in number, and maturation arrest. Vacuolations of interstitial tissue and Leydig cells were also observed. Percent area of fibrosis and caspase-3 immunoexpression was significantly increased. Ultrastructurally, irregular tubular basement membrane and damaged germ cells were found. The spermatogenic, Sertoli, and Leydig cells showed irregular shrunken nuclei, cytoplasmic vacuolations, and swollen mitochondria. MSG + SE group showed much better histological and ultrastructural picture and improvement of the measured biochemical and morphometric parameters. Percent area of caspase-3 immunoexpression was significantly decreased. In conclusion, sodium selenite ameliorated the testicular damaging effect of MSG through reduction of oxidative stress and apoptosis.