In pediatric patients requiring vascular reconstruction, the development of a cell-based tissue-engineered vascular patch (TEVP) has great potential to overcome current issues with nonliving graft materials. Determining the optimal cell source is especially critical to TEVP success. In this study, we compared the ability of human aortic smooth muscle cells (HuAoSMCs) and human mesenchymal stem cells (hMSCs) to form cell sheets on thermoresponsive poly(N-isopropylacrylamide) (PIPAAm) substrates. hMSCs treated with transforming growth factor beta 1 (TGFβ1) and ascorbic acid (AA) had higher expression of SMC-specific proteins compared to HuAoSMCs. hMSCs also had larger cell area and grew to confluence more quickly on PIPAAm than did HuAoSMCs. hMSCs typically formed cell sheets in 2-3 weeks and had greater wet tissue weight and collagen content compared with HuAoSMC sheets, which generally required growth for up to 5 weeks. Assays for calcification and alkaline phosphatase activity revealed that the osteogenic potential of TGFβ1+AA-treated hMSCs was low; however, Alcian Blue staining suggested high chondrogenic behavior of TGFβ1+AA-treated hMSCs. Although hMSCs are promising for cell-based TEVPs in their ability to form robust tissue with significant extracellular matrix content, improved control over hMSC behavior will be required for long-term TEVP success.