ObjectiveTo investigate the association of sleep disorders with the development and progression of nonalcoholic fatty liver disease （NAFLD）. MethodsA total of 1 868 participants from the health examination cohort and fatty liver cohort of Beijing Friendship Hospital from June 2022 to June 2023 were enrolled as subjects. Related data were collected from all subjects， including age， sex， education level， chronic medical history， and biochemical parameters， and all subjects completed Pittsburgh Sleep Quality Index （PSQI） scale independently. According to the diagnostic criteria， the subjects were divided into non-NAFLD group with 1 122 subjects and NAFLD group with 746 subjects， and according to the stage of progression， the patients in the NAFLD group were further divided into simple fatty liver group （SFL group with 624 subjects） and nonalcoholic steatohepatitis （NASH） group with 122 subjects. A one-way analysis of variance or the Kruskal-Wallis H test was used for comparison of continuous data between three groups. The chi-square test was used for comparison of categorical data between the three groups. The binary Logistic regression analysis was used to investigate the association between sleep factors and NAFLD， and the multinomial Logistic regression analysis was used to investigate the association between sleep factors and the different stages of NAFLD； two multivariate models were constructed for adjustment of potential confounding factors， i.e.， an age-sex adjustment model and a multivariate adjustment model， and the multivariate adjustment model adjusted the factors of age， sex， education level， smoking， diabetes， hypertension， body mass index （BMI）， triglyceride （TG）， and high-density lipoprotein cholesterol （HDL-C）. ResultsThere were significant differences in age， sex， BMI， education level， smoking， diabetes， hypertension， alanine aminotransferase， TG， and HDL-C between the non-NAFLD， SFL， and NASH groups （all P<0.05）. There were also significant differences between the three groups in the total score of PSQI scale and the proportion of subjects with a score of 0‍ ‍—‍ ‍3 points for the 7 sleep components （all P<0.05）. The multivariate adjustment model showed no significant association between sleep disorders and SFL， while long sleep latency （odds ratio ［OR］=4.04， 95% confidence interval ［CI］： 2.33‍ ‍—‍ ‍7.03， P<0.001）， short sleep duration （OR=3.53， 95%CI： 1.83‍ ‍—‍ ‍6.82， P<0.001）， and severe sleep disorders （OR=2.96， 95%CI： 1.48‍ ‍—‍ ‍5.93， P=0.002） were closely associated with the risk of NASH. ConclusionOverall sleep condition and its components of sleep disorders are not significantly associated with the simple fatty liver； however， long sleep latency， short sleep duration， and severe sleep disorders can increase the risk of NASH， which should be taken seriously in clinical practice.