► Vitamin D plays diverse roles in brain development and function. ► A range of adverse brain outcomes have been associated with low levels of vitamin D. ► Animal models have proven useful in determining the role of vitamin D in the brain. ► Dopamine appears to be susceptible to developmental vitamin D deficiency. ► Further research is required to determine the relevance of vitamin D deficiency to human neuropsychiatric disorders. A role for vitamin D in brain development and function has been gaining support over the last decade. Multiple lines of evidence suggest that this vitamin is actually a neuroactive steroid that acts on brain development, leading to alterations in brain neurochemistry and adult brain function. Early deficiencies have been linked with neuropsychiatric disorders, such as schizophrenia, and adult deficiencies have been associated with a host of adverse brain outcomes, including Parkinson’s disease, Alzheimer’s disease, depression and cognitive decline. This review summarises the current state of research on the actions of vitamin D in the brain and the consequences of deficiencies in this vitamin. Furthermore, we discuss specific implications of vitamin D status on the neurotransmitter, dopamine.