Background Exposure to electromagnetic radiation (EMR) is closely associated with neurobehavioral disorders. Vitamin D (Vit.D) has neuroprotective functions. This work aimed to clarify the effect of Vit. D3 on the cognition of rats exposed to wireless fidelity (Wi-Fi) and explore the possible underlying mechanisms. Background Exposure to electromagnetic radiation (EMR) is closely associated with neurobehavioral disorders. Vitamin D (Vit.D) has neuroprotective functions. This work aimed to clarify the effect of Vit. D3 on the cognition of rats exposed to wireless fidelity (Wi-Fi) and explore the possible underlying mechanisms. Method Forty male albino rats were divided into 4 equal groups: normal control (NC), NC+Vit.D, Wi-Fi, and Wi-Fi+Vit.D. The rats in NC+Vit.D and in Wi-Fi+Vit.D groups were treated with Vit.D3 (500 IU/kg) orally once daily for 40 days, the Wi-Fi and Wi-Fi +Vit.D groups were subjected to EMR of 2.45 GHz for two hours per day for 40 days. Rat neurobehavior tests were done then isolation of hippocampus was performed to assay hippocambal tumor necrosis factor-α (TNF-α), superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and malondialdehyde (MDA). apoptosis-related gene (BAX and BCL2), cyclic AMP-response element binding protein (CREB), autophagy genes of LC3 and P62 expressions were assessed. Immunohistochemistry for caspase-3 and histopathology of the rat hippocampus were examined. Results Wi-Fi exposure induced anxiety and memory dysfunction in rats associated with histological signs of neuronal degeneration in their hippocampus, Treatment with Vit.D significantly improved cognitive dysfunction and decreased neuronal damage. The Wi-Fi group showed significantly higher MDA, TNF-α levels, caspase-3 immune reactions, and BAX, P62, and BAX/BCL-2 ratio expression. However; a significant decrease in GSH, SOD, CAT, and expression of BCL2, CREB, and LC3. Treatment with Vit.D significantly reversed the parameters mentioned above. Conclusion Administering Vit.D3 can protected against cognitive impairment associated with Wi-Fi radiation exposure.