Objective: To investigate the association between edentulism and the risk of social isolation in middle-aged and elderly populations, provide empirical evidence for formulating social isolation prevention and intervention policies targeting edentulous middle-aged and elderly populations. Methods: Data were derived from the baseline survey (2011) and three follow-ups (2013, 2015, 2018) of the China Health and Retirement Longitudinal Study (CHARLS). Participants were enrolled in the follow-up from the baseline. Those identified as socially isolated in any of the follow-up surveys conducted in 2013, 2015, or 2018 were considered to have reached the endpoint; otherwise, the follow-up was continued until the end of the 2018 survey; 9 870 individuals were ultimately included. Subjects were grouped by edentulism status. Chi-square test and multivariate Cox regression analysis were performed using Stata 17.0. Results: During a median follow-up of 6.54 years, 1 800 cases of social isolation occurred, with an incidence rate of 18.23%（17.47%~18.99%）. Multivariate Cox regression showed that edentulism was associated with an increased risk of social isolation (HR=1.21, 95% CI: 1.03-1.42) after adjusting for confounders. Subgroup analysis revealed population heterogeneity. Sensitivity analyses confirmed the stability of the results. Conclusion Edentulism is associated with an increased risk of social isolation in middle-aged and elderly adults.