Multiple sclerosis (MS) is an  chronic autoimmune and demyelinating disease of the central nervous system (CNS), marked by lymphocyte migration across the blood-brain barrier (BBB). Active vitamin D acts as an immune modulator through the vitamin D receptor (VDR), whose polymorphisms may influence disease progression and response to treatments such as natalizumab (NTZ). NTZ is a monoclonal antibody that inhibits immune cell migration into the CNS by targeting integrins α4β1 and α4β7 integrins. This study aimed to assess the association between single nucleotide polymorphisms (SNPs) rs7975232, rs731236, rs11568820, and rs4516035 in the VDR gene and clinical response to NTZ in MS patients. Peripheral blood (4 mL) was collected in EDTA tubes for leukocyte isolation. DNA was extracted and quantified by spectrophotometry (NanoVue), and SNP genotyping was performed using real-time qPCR (QuantStudio™️ 5) and, TaqMan®️ probes). Cytokines IL-4, IL-6, IL-18, and IFN-γ were measured in plasma from 40 randomly selected NTZ responders using a Multiplex xMAP assay (Bio-Plex 200®️, Bio-Rad). Among 116 patients, 89% responded to NTZ. The rs7975232 CC genotype was linked to therapeutic failure (p=0.0416), while rs731236 AA was associated with a positive response (p=0.0003). For rs11568820, the GG genotype correlated with good response, and GA with poor response. No significant association was found for rs4516035. Cytokine levels did not significantly differ across genotypes. Only rs731236 conformed to Hardy-Weinberg equilibrium, and strong linkage disequilibrium was observed between rs7975232 and rs731236. These findings suggest that VDR polymorphisms may modulate inflammatory activity in theinfluence CNS and, consequently, affect MS progression and the efficacy of NTZ response. and CNS inflammation. VDR emerges as a promising pharmacogenetic biomarker, aiding treatment personalization and patient stratification in MS.