Nucleotide-binding oligomerization domain protein 2 (NOD2), an intracellular pattern recognition receptor, plays important roles in inflammation and cell death. Previously, we showed that NOD2 is expressed in vascular smooth muscle cells (VSMCs) and NOD2 deficiency promoted VSMC proliferation, migration, and neointimal formation after vascular injury. However, its role in endoplasmic reticulum (ER) stress-induced cell death in VSMCs remains unclear. Here, we evaluated ER stress-induced viability of mouse primary VSMCs. NOD2 deficiency increased ER stress-induced cell death and expression of the apoptosis mediators, cleaved caspase-3, Bax, and Bak in VSMCs in the presence of the ER stress inducer tunicamycin (TM). In contrast, expression of the apoptosis mediators cleaved caspase-3, Bax, and Bak was decreased in NOD2-overexpressed VSMCs. We found that one of the unfolded protein response branches, the IRE-1-XBP1 pathway, was decreased in NOD2-deficient VSMCs and reversed in NOD2-overexpressed VSMCs in the presence of TM. Furthermore, NOD2 deficiency reduced the expression of XBP1 target unfolded protein response genes such as GRP78, PDI-1, and Herpud1, improving cell survival. Taken together, these data suggest that the induction of ER stress through NOD2 expression protect against TM-induced cell death in VSMCs. These results may contribute to a new paradigm in vascular homeostasis.