This descriptive study aimed to explore the mediating role of experiential avoidance in the association between diabetes distress and self-stigma in Korean patients with diabetes mellitus type 2. The study included 196 participants with diabetes mellitus type 2, diagnosed by an endocrinologist. Data were collected from 20 September to 31 September 2021, using an online self-report questionnaire focusing on diabetes distress, diabetes self-stigma, and experiential avoidance. For the mediating effect analysis, a three-step hierarchical multiple analysis was performed using SPSS, and the mediating effect was verified using SPSS PROCESS Macro. The findings revealed that the average scores for diabetes distress, self-stigma, and experiential avoidance were 3.01 ± 0.66, 2.57 ± 0.82, and 3.65 ± 0.55, respectively. Positive correlations were observed among diabetes distress, self-stigma, and experiential avoidance. Specifically, experiential avoidance partially mediated the relationship between diabetes distress and self-stigma, accounting for 47.7% of the variance. These findings reveal that it is crucial to focus on countering experiential avoidance to assist patients with diabetes mellitus type 2 in overcoming the self-stigma and distress related to their condition. In addition, it is necessary to develop a gradual and tailored program aimed at reducing experiential avoidance.