Objective Adiponectin (APN) circulates as high‐molecular weight (HMW), medium‐molecular weight (MMW), and low‐molecular weight (LMW) forms. Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease. Currently, the role of LMW, MMW, and HMW APN remains largely unclear in NAFLD. Methods We examined the variation of these forms and analyzed the related clinical characteristics in NAFLD. A total of 63 male NAFLD patients (mean age: 43.00 ± 6.10 years) and 70 healthy male subjects (mean age: 42.53 ± 7.98 years) were included in the study. Total APN and other clinical characteristics were measured. The changes in HMW, MMW, and LMW APN were determined in NAFLD patients and NAFLD patients on a high‐fat diet, and the association between the groups was further analyzed. Results Decreased levels of total APN and three APN isoforms were found in NAFLD. Significantly decreased levels of HMW (P