This study aimed to examine the association between dietary niacin intake and the prevalence of epilepsy. We conducted a cross-sectional analysis of 14,236 participants from the National Health and Nutrition Examination Survey (NHANES) 2013-2018. Multivariable logistic regression, generalized additive models, and subgroup analyses were employed to assess the relationship. An inverse association was found between dietary niacin intake and the prevalence of epilepsy: for every 10 mg/day increase, the odds of having epilepsy were reduced by 15 % (OR = 0.85, p = 0.0266). Participants in the highest quintile of niacin intake had a significantly lower odds of epilepsy compared to those in the lowest quintile (OR = 0.45, p = 0.0187). This negative association remained consistent across groups with diverse demographic characteristics, medical conditions, and lifestyle choices. Our findings suggest a possible inverse association between dietary niacin intake and the prevalence of epilepsy.