Background: Statins have beneficial pleiotropic effects, including reducing intimal hyperplasia (IH), but off-target effects remain a concern. Here, we tested the hypothesis that chitosan-functionalized polymeric nanoparticles (NPs) loaded with simvastatin (SL-cNPs) would (1) readily associate with endothelial cells (ECs) and vascular smooth muscle cells (VSMCs); (2) affect EC and VSMC function; and (3) reduce IH compared to systemic simvastatin. Methods: Human aortic ECs and VSMCs were cultured with fluorescently labeled SL-cNPs. The association of SL-cNPs was assessed by immunostaining and flow cytometry. The effect of SL-cNPs, empty cNPs (E-cNPs), and free simvastatin on cells was determined using qRT-PCR for RhoA and RhoB. Carotid artery balloon-injured rats were treated intraoperatively with intraluminal saline, E-cNPs, low- or high-dose SL-cNPs, periadventitial high-dose SL-cNPs, or with pre- and post-operative oral simvastatin plus intraoperative intraluminal saline or low-dose SL-cNPs. Rats were euthanized (day 14) and IH was quantified. Results: SL-cNPs readily associated with ECs and VSMCs. Low- and high-dose SL-cNPs induced significant increases in EC and VSMC RhoA gene expression. High-dose SL-cNPs induced a significant increase in EC RhoB expression, while free simvastatin and low- and high-dose SL-cNPs significantly increased RhoB expression in VSMCs. In vivo, oral simvastatin plus intraluminal SL-cNPs significantly reduced IH compared to controls. Conclusions: cNPs can be used as a vehicle to locally deliver statins to vascular cells. However, other NP formulations may be preferential for IH reduction given only the combination of oral simvastatin and SL-cNPs effectively reduced IH.