Abstract Background and Aim Metabolic dysfunction‐associated steatotic liver disease (MASLD) is recently introduced to better highlight the pathogenic significance of cardiometabolic dysfunction, as compared with non‐alcoholic fatty liver disease. This study aimed to investigate the association between low thyroid function and MASLD in the new context. Methods We recruited 2901 participants for our retrospective cohort study from 2016 to 2021. Participants were divided into strict‐normal thyroid function and low thyroid function groups (low‐normal thyroid function, subclinical hypothyroidism) based on initial thyroid stimulating hormone (TSH) levels, respectively. Cox regression models were used to estimate the hazard ratios (HRs) and 95% CI. Results During a median follow‐up of 15.6 months, 165 (8.9%) strict‐normal thyroid function subjects and 141 (13.4%) low thyroid function subjects developed MASLD; this result was statistically relevant (P