Background Non-alcoholic steatohepatitis (NASH) has been recognised as a significant form of chronic liver disease and a common cause of cirrhosis and hepatocellular carcinoma, resulting in a considerable financial burden on healthcare resources. Currently, there is no information regarding the economic burden of NASH in low-and middle-income countries (LMICs). The aim of this study was to estimate the economic burden of NASH in Thailand as a lesson learned for LMICs. Methods To estimate the healthcare costs and prevalence of NASH with significant fibrosis (fibrosis stage≥ 2) in the general Thai population, an eleven-state lifetime horizon Markov model with 1-year cycle length was performed. The model comprised Thai population aged 18 years and older. The cohort size was based on Thailand Official Statistic Registration Systems. The incidence of NASH, transitional probabilities, and costs-of-illness were based on previously published literature, including systematic reviews and meta-analyses. The age-specific prevalence of NASH was based on Thai NASH registry data. Costs were expressed in 2019 US Dollars ().Asweundertookanalysisfromthepayerperspective,onlydirectmedicalcostswereincluded.Allfuturecostswerediscountedatanannualrateof3%.Aseriesofsensitivityanalyseswereperformed.ResultsTheestimatedtotalnumberofpatientswithsignificantNASHwas2.9millioncasesin2019,basedonaNASHprevalenceof5.74%.ThetotallifetimecostofsignificantNASHwas 15.2 billion (5,147percase),representingapproximately3%ofthe2019GDPofThailand.TheprobabilisticsensitivityanalysisshowedthatthelifetimecostsofsignificantNASHvariedfrom 11.4 billion to 18.2billion.ConclusionsTheeconomicburdenassociatedwithNASHissubstantialinThailand.ThispromptscliniciansandpolicymakerstoconsiderstrategiesforNASHpreventionandmanagement.