Liver fibrosis plays a key role in the progression of non-alcoholic fatty liver disease to cirrhosis. Considering weight change is known to be closely associated with increased risk of liver fibrosis, we aimed to address a gap in evidence regarding the existence of this association in patients with type 2 diabetes (T2D).We included data on 622 T2D patients and 1618 non-T2D participants from the 2017-2018 cycle of the National Health and Nutrition Examination Survey (NHANES). We assessed liver fibrosis by the median values of liver stiffness measurement (LSM). According to the participants' body mass index (BMI) at age 25 (early adulthood), 10 years prior (middle adulthood), and at the 2017-2018 cycle (late adulthood), we categorised weight change patterns into stable non-obese, weight loss, weight gain, and stable obese. We applied logistic regression to association analysis and used population attributable fraction (PAF) to analyses hypothetical prevention regimens.The prevalence of liver fibrosis was higher in T2D patients (23.04%) than in non-T2D participants (6.70%), while weight change was associated with a greater risk of fibrosis in the former compared to the latter group. Compared with T2D patients in the stable non-obese group, stable obese individuals from 10 years prior to the 2017-2018 cycle had the highest risk of developing liver fibrosis, corresponding to an adjusted odds ratio (aOR) of 3.13 (95% confidence interval = 1.84-5.48). Absolute weight change patterns showed that the risk of liver fibrosis was highest (aOR = 2.94) when T2D patients gained at least 20 kg of weight from 10 years prior to 2017-2018 cycle.Obesity in middle and late adulthood is associated with an increased risk of T2D complicated with liver fibrosis.Copyright © 2023 by the Journal of Global Health. All rights reserved.