Heparan sulfate proteoglycans are abundant molecules in the extracellular matrix and at the cell surface. Heparan sulfate chains are composed of groups of disaccharides whose side chains are modified through a series of enzymatic reactions. Deletion of these enzymes alters heparan sulfate fine structure and leads to changes in cell proliferation and tissue development. The role of heparan sulfate modification has not been explored in the vessel wall. The goal of this study was to test the hypothesis that altering heparan sulfate fine structure would impact vascular smooth muscle cell (VSMC) proliferation, vessel structure, and remodeling in response to injury. A heparan sulfate modifying enzyme, N-deacetylase N-sulfotransferase1 (Ndst1) was deleted in smooth muscle resulting in decreased N- and 2-O sulfation of the heparan sulfate chains. Smooth muscle specific deletion of Ndst1 led to a decrease in proliferating VSMCs and the circumference of the femoral artery in neonatal and adult mice. In response to vascular injury, mice lacking Ndst1 exhibited a significant reduction in lesion formation. Taken together, these data provide new evidence that modification of heparan sulfate fine structure through deletion of Ndst1 is sufficient to decrease VSMC proliferation and alter vascular remodeling.