Factors contributing to aggressive behavior in vulvar squamous cell carcinoma (vSCC) are poorly defined; however, a recent study has shown that vSCCs with an infiltrative pattern of invasion and fibromyxoid stroma are associated with worse outcomes than tumors with a pushing or nested pattern of invasion and lymphoplasmacytic stroma. Epithelial-mesenchymal transition (EMT) has been associated with tumor progression in a number of malignancies, and this study proposes that EMT contributes to tumor aggressiveness in this subset of vSCC. Immunohistochemistry was used to detect nuclear localization of β-catenin, loss of E-cadherin, and presence of vimentin in 58 cases of vSCC. The association of these phenotypic changes with pathologic features and clinical outcomes was tested using Fisher’s exact and χ 2 analyses (significance at p ≤0.05). EMT-associated features were identified in 45 of 58 cases (78%) with 28 cases exhibiting more than one feature. Nuclear β-catenin and presence of vimentin were significantly more likely to occur in tumors with an infiltrative pattern of invasion or a fibromyxoid stromal response. Loss of E-cadherin was significantly associated with an infiltrative pattern, but not a fibromyxoid stroma. Risk for tumor recurrence was significantly increased in tumors with nuclear localization of β-catenin alone or in tumors displaying multiple EMT-associated features. These results suggest that the development of an EMT may be a mechanism by which infiltrative vulvar tumors with a fibromyxoid stromal response behave more aggressively and convey worse outcomes than tumors that do not exhibit these pathologic features.