Background: The epithelial-mesenchymal transition (EMT) is the process where cells lose their epithelial features and acquire properties of typical mesenchymal cells. The dissociation of tumor cells due to changes in cell-cell adhesion is one of the key principles of tumor invasion and EMT. Thus, the knowledge of the molecular features of EMT in keratocyst odontogenic tumor (KOT) can provide useful markers to aid in the diagnosis and prognosis and perhaps contribute to an alternative therapeutic approach as it shows an aggressive clinical behavior and high recurrence rates. This study aimed to evaluate the EMT in KOT by the immunoexpression of E-cadherin, N-cadherin, Snail, and Slug and comparing to radicular cysts and dental follicles. Methods: Thirty-two KOTs, 15 radicular cysts, and 08 dental follicles were used for immunohistochemistry, evaluating the extent, intensity, labeling pattern, cellular compartment in the epithelium and stroma, and the presence of inflammation. Results: E-cadherin was preserved in most cases of keratocystic odontogenic tumor. N-cadherin was increased in the tumor epithelium, a result that was positively correlated with the heterogeneous and nuclear immunoexpression of Slug in the epithelium; Slug also correlated with high Snail immunoexpression. N-cadherin was positively correlated with Slug in the stroma of keratocystic odontogenic tumors. Conclusions: The high immunoexpression of Snail and nuclear Slug in keratocystic odontogenic tumors suggests these proteins as transcription factors without necessarily participating in 'cadherin switching'. However, the knowledge of their induction of the epithelial-mesenchymal transition in odontogenic tumors is still limited.