Objectives <p>Edentulism, the complete loss of natural teeth, profoundly affects the oral health and quality of life of older adults. Socio-economic disparities are a critical determinant of oral health outcomes. This study assessed and decomposed socio-economic inequalities in edentulism among community-dwelling older adults in Tehran in 2023.</p> Materials and methods <p>The analytical study was employed data from the Oral Health Utilization Survey. Participants aged ≥ 60 years (<i>N</i> = 478) were selected using a stratified random sampling method. Data were collected using a validated questionnaire including socio-demographic variables, individuals’ oral health-related behaviors and oral health information, and outcome variable of edentulism. The Erreygers-corrected concentration index (ECI) was employed to demonstrate disparity and its gradient qualitatively and quantitatively. A decomposition approach based on logit model was used, and analysis was conducted by STATA 16.</p> Results <p>The participants’ mean age was 68.9 (SD = 6.4) years. Approximately 48.0% of the participants reported no dental care utilization. The ECI was − 0.23 (95% CI: -0.31 to -0.15), indicating a pro-poor concentration of edentulism. Key contributors included wealth status (72.08%), chewing difficulties (-17.30%), and halitosis (5.02%). Notably, older age, living alone, and lower socio-economic status were associated with higher odds of edentulism.</p> Conclusion <p>Edentulism among older adults in Tehran is disproportionately concentrated among socio-economically disadvantaged groups. Edentulism was highly contributed to age, living arrangements, socio-economic status, and difficulty while chewing. Targeted public health interventions addressing socio-economic disparities and oral health promotion are essential to improve equity in oral health outcomes for the aging population.</p>