Objective: To investigate the predictive value of EZH2 expression for malignant transformation in oral leukoplakia (OLK) and to provide a reference for clinical practice. Methods: This study was approved by the institutional ethics committee, and informed consent was obtained from all participants. A total of 114 patients diagnosed with OLK by pathological examination and treated at our hospital between November 2020 and July 2022 were initially enrolled. After excluding those with incomplete data or follow-up, 105 participants were included in the final analysis, comprising 14 in the high EZH2 expression group and 91 in the low EZH2 expression group. Histopathological examination of oral mucosa and immunohistochemical detection of EZH2 protein expression were performed. The follow-up period was 30 months; participants were followed until malignant transformation occurred or until the end of follow-up, at which point they were withdrawn from the study. The exposure factor was the level of EZH2 protein expression, and the outcome was the malignant transformation rate of OLK. Differences in EZH2 expression levels and transformation outcomes were analyzed. Results: There were no statistically significant differences between the high and low EZH2 expression groups in terms of age, sex, history of systemic disease, lifestyle habits, psychological status, diet, and sleep conditions (P > 0.05). Lesions in the high EZH2 expression group were mainly located on the ventral tongue, while in the low EZH2 expression group, they were more commonly found on the dorsal tongue and buccal mucosa. The malignant transformation rate was 28.6% (4/14) in the high expression group and 8.8% (8/91) in the low expression group; these differences were not statistically significant (P=0.053). In univariate Cox regression analysis, the risk of malignant transformation in the high EZH2 expression group was 3.647 times that of the low EZH2 expression group (HR = 3.647, 95% CI: 1.097-12.120, P<0.05). Kaplan-Meier survival analysis showed that over the 30-month follow-up period, the cancer-free survival rate in the high EZH2 expression group was 19.8% lower than in the low expression group, and the difference was statistically significant (P<0.05). In multivariate Cox regression analysis, only moderate and severe epithelial dysplasia were identified as independent risk factors for malignant transformation. The risk of malignant transformation in the moderate and severe dysplasia groups was 10.695 and 13.623 times higher, respectively, than in the mild dysplasia group (HR = 10.695, 95% CI: 2.270-50.396, P<0.05; HR=13.623, 95% CI: 1.918-96.774, P<0.05). EZH2 high expression was not an independent risk factor in the multivariate model (HR= 2.528, 95% CI: 0.752-8.500, P = 0.134). Conclusion High EZH2 protein expression is a risk factor for the malignant transformation of OLK but does not have independent predictive value.