Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent condition in the general population. Although recent studies have demonstrated a link between NAFLD and lipoprotein(a), a low-density lipoprotein-like particle synthesized in the liver, its precise physiological role and mechanism of action remain unclear. This study aimed to investigate the relationship between lipoprotein(a) levels and development of NAFLD and hepatic fibrosis in Korean adults. A total of 1501 subjects who underwent abdominal ultrasonography at least twice as part of a health checkup program were enrolled. Biochemical and ultrasonography results were analyzed longitudinally, and the degree of hepatic fibrosis was calculated in subjects with NAFLD using serum biomarkers, such as fibrosis-4 (FIB-4). During the 3.36-year follow-up period, 352 patients (23.5%) were diagnosed with NAFLD. The subjects were categorized into 4 groups based on their lipoprotein(a) levels. Remarkably, the incidence of NAFLD decreased as the lipoprotein(a) levels increased. Following logistic regression analysis and adjustment for various risk factors, the odds ratio for the development of NAFLD was 0.625 (95% CI 0.440–0.888; P = .032) when comparing the highest to the lowest tertile of lipoprotein(a). However, no significant association was observed between the occurrence of hepatic fibrosis and lipoprotein(a) levels in subjects with NAFLD. Lipoprotein(a) levels have been identified as a significant predictor of NAFLD development. Additional large-scale studies with extended follow-up periods are required to better understand the effect of lipoprotein(a) on NAFLD and hepatic fibrosis.