Suicide attempts are known to peak in the spring, overlapping with the time of year when 25-hydroxyvitamin D [25(OH)D] levels are at their nadir in the northern hemisphere because of negligible skin production of vitamin D owing to low levels of ultraviolet B radiation. Low levels of 25(OH)D, the vitamin D metabolite used to diagnose vitamin D deficiency, have been associated with certain pro-suicidal factors such as exacerbation of depression, anxiety, psychosis, and certain medical conditions. Therefore, we hypothesize that vitamin D deficiency could also be associated with increased risk of completed suicides. Here, we briefly review the literature on vitamin D, its deficiency, and its reported association with certain risk factors for suicide.