The pathogenesis of amyotrophic lateral sclerosis (ALS) is multifactorial and a treatment targeting only one aspect of the disease is unlikely to be beneficial. Vitamin D is safe and may delay progression of ALS by acting on several aspects of the disease. In this article we explore how vitamin D may promote VGEF, IGF-1 and axonal regeneration delaying ALS progression. In addition, we discuss how vitamin D may increase calcium binding protein in motor neuron cells conferring a greater resistance to the underlying disease process, as seen in the oculomotor nerve and Onuf's nucleus. Finally, we discuss vitamin D immunomodulator role, decreasing the reactive gliosis in ALS.