Vitamin D deficiency has been estimated to affect roughly 30% to 50% of the global population and thus labeled as a silent pandemic. In addition to its role in skeletal and calcium homeostasis, vitamin D has been implicated in brain functioning across both preclinical research and human populations studies. These findings have also been extended to various neurodevelopmental and neuropsychiatric conditions. Furthermore, these individuals tend to display diminishing cognition symptoms. In this regard, this review is dedicated to address the relationship between vitamin D and dementia, mood disorders, and the various neuropsychological disorders of psychosis. The review takes both preclinical and clinical studies into consideration. While there are many literature suggesting the critical role of vitamins in cognition on the above said diseases, it is still premature to unequivocally postulate the role of vitamin D on cognitive symptoms. Further research is necessary to establish this association, including the need to increase the ecological validity of animal models, delineating the core cognitive symptoms associated with the disorders, and establishing the optimal source of vitamin D consumption.