Vitamin D deficiency enhanced lung metastasis in vivo and markers of epithelial‐mesenchymal transition (EMT) in vitro. Mechanisms identified included co‐localization of chemokine CXCL12 and its receptor CXCR4 in the lung metastatic niche and increased expression of pSTAT3 and ZEB1 (EMT drivers). Here, CXCR4 is linked to vitamin D deficiency.