The emergence of new data suggests that the benefits of Vitamin D extend beyond healthy bones. This paper looks at Vitamin D and its role in the aetiology and maintenance of chronic pain states and associated comorbidities. The interfaces between pain and Vitamin D and the mechanisms of action of Vitamin D on pain processes are explored. Finally the association between Vitamin D and pain comorbidities such as sleep and depression is investigated. The paper shows that Vitamin D exerts anatomic, hormonal, neurological, and immunological influences on pain manifestation, thereby playing a role in the aetiology and maintenance of chronic pain states and associated comorbidities. More research is necessary to determine whether Vitamin D is useful in the treatment of various pain conditions and whether or not the effect is limited to patients who are deficient in Vitamin D.