Lower potassium intake is considered to be correlated with diabetes incidence. However, few studies have investigated the effect of potassium intake on metabolic syndrome (MetS). Data was taken from the Korean National Health and Nutritional Examination Survey (2008-2010) using weighted adjustment. MetS was defined as per the revised National Cholesterol Education Program criteria. Homeostasis model assessment indices were calculated to diagnosis insulin resistance (IR). A total of 16,637 participants (44 ± 0.25 years) were included. Women ingested lower amounts of potassium (2.71 ± 0.02 g/day) than men (3.45 ± 0.03 g/day). A curvilinear association between potassium intake and MetS prevalence was found among women. Women with less than the Adequate Intake (4.7 g/day) of potassium had an 11% risk reduction for MetS (adjusted odds ratio [OR], 0.89; 95% confidence interval [CI], 0.82-0.96; P = 0.004) and a 10% risk reduction for IR (OR, 0.90; 95% CI, 0.82-0.99; P = 0.026) for every 1 g/day potassium increase. Compared with the reference group (3.5-4.5 g/day), potassium intake was inversely associated with an increased risk of MetS (1.5-2.5 g/day; OR, 1.29; 95% CI, 1.02-1.63; P = 0.035; <1.5 g/day; OR, 1.40; 95% CI, 1.06-1.85; P = 0.017) and IR (<1.5 g/day; OR, 1.36; 95% CI, 1.05-1.76; P = 0.021). This relationship was more prominent in postmenopausal women, but not observed among men. Higher potassium intake is significantly associated with a lower MetS prevalence in women, and IR is believed to be connected.