This study was conducted to assess the relationship between metabolic syndrome (MetS) and beta-cell function in nondiabetic Korean women. This study included 2,507 women (premenopausal women, 1,359; postmenopausal women, 1,148) who were aged ≥20 and used 2015 Korean National Health and Nutrition Examination Survey (KNHANES) data. Key study results were as follows: first, in both premenopausal and postmenopausal women, after adjusting for related variables [except body mass index (BMI)], MetS ( < 0.001) and metabolic syndrome score (MSS;  < 0.001) were positively associated with the homeostasis model assessment of beta-cell function (HOMA-B) levels. Second, in premenopausal women, when further adjusted for BMI, MetS ( = 0.002) and MSS ( < 0.001) were also positively associated with HOMA-B levels. However, in postmenopausal women, when further adjusting for BMI, the associations of MetS ( = 0.322) or MSS ( = 0.855) and HOMA-B levels were no longer significant. Metabolic syndrome was positively associated with beta-cell function in nondiabetic Korean premenopausal women, but not in Korean postmenopausal women.