The evidence regarding the relationship between dietary niacin intake and kidney stones is limited. This study aims to investigate the association of dietary niacin intake with the prevalence of kidney stones among adults in the United States. The present cross-sectional study used data from the National Health and Nutrition Examination Survey (NHANES) 2007-2018. Dietary niacin intake was obtained from the first 24-h dietary recalls. The history of kidney stones was assessed by a questionnaire. Weighted logistic regression, restricted cubic splines (RCS) and stratified analysis were used to evaluate the relationship between dietary niacin intake and the risk of kidney stones. A total of 28,508 participants were included. In the full adjusted model, an inverse relationship between dietary niacin intake and kidney stones was observed. Compared to individuals in the lowest dietary niacin intake group, those in the highest group had lower odds of developing kidney stones (OR = 0.78, 95% CI = 0.63-0.97). RCS analysis showed a L-shaped relationship between niacin intake and kidney stones (P for non-linearity = 0.047). Stratified analysis indicated that this inverse associations appeared to be stronger among participants aged blew 60 years (P for interaction <
0.05). This cross-sectional study indicated that dietary niacin intake was associated with a decreased risk of kidney stones in US adults, especially in individuals under 60 years of age. Our findings suggest that appropriate doses of niacin intake may reduce the risk of kidney stones. Further research is required to confirm our findings and clarify the casual relationship.