Purpose: There have been little researches examining the role of family functioning on psychological outcomes in the field of adult epilepsy. We determined whether family functioning is correlated with felt stigma in adults with epilepsy. Methods: In this cross-sectional study, adults with epilepsy and their caregivers were recruited. Data were collected using the Family Adaptability and Cohesion Evaluation Scale (FACES) Ill, the Family adaptation, partnership, growth, affection, and resolve (APGAR) questionnaire, the Stigma Scale for Epilepsy (SS-E), the modified questionnaire for episodes of discrimination, and the Beck Depression Inventory. Family functioning was measured by the caregivers. Results: A total of 273 adult patients and their primary caregivers were included. Multivariate logistic analyses showed that family cohesion and excellent family functioning were negatively correlated with felt stigma after controlling for confounding variables. Enacted stigma, depressive symptoms, and university education were also significant. Interaction between enacted stigma and family cohesion on felt stigma was significant (p = 0.049). Family cohesion was negatively correlated with felt stigma only in the patients with enacted stigma (p = 0.011). Conclusions: Family functioning especially family cohesion may have protective effects against development of felt stigma in adults with epilepsy. Such protecting effects against felt stigma may be different according to enacted stigma. This understanding is helpful for developing effective psychosocial interventions to reduce felt stigma in patients with epilepsy.