BackgroundMajority of dietary intake in United States adults comes from ultraprocessed foods (UPFs), which have been linked to several adverse health outcomes. Gallstone disease is highly prevalent and constitutes a significant burden to the United States health system but remains understudied. ObjectivesThis study aimed to investigate the association between UPF consumption and incident gallstone disease risk. MethodsIn this analysis, 44,149 males in the Health Professionals’ Follow-up Study (HPFS: 1986–2022), 71,145 females in the Nurses’ Health Study (NHS: 1986–2021), and 90,932 females in the NHS II (1991–2021) were prospectively followed. Dietary intake was quadrennially assessed with semiquantitative food frequency questionnaires and used to identify UPFs. The primary outcome was defined as cholecystectomy. Cox proportional hazards model was used to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). ResultsBaseline median age was 54 y in HPFS, 53 y in NHS, and 36 y in NHS II. We identified 32,374 incident gallstone disease cases over 5,077,059 person-years. Participants in the highest UPF quintile had a higher incidence of gallstone disease than those in the lowest quintile (aHR: 1.29; 95% CI: 1.24, 1.36; P < 0.001). Incremental risk of incident gallstone disease was 2.8% per daily serving (95% CI: 2.4%, 3.2%; P < 0.001). This risk was driven by sugar-sweetened beverages and artificially sweetened beverages on UPF subgroup analyses. The proportion of risk mediated by obesity was 12.8% (95% CI: 7.7%, 20.5%; P < 0.001) in HPFS, 14.3% (95% CI: 10.4%, 19.4%; P < 0.001) in NHS, and 39.4% (95% CI: 31.2%, 48.1%; P < 0.001) in NHS II. The partial population attributable risk was estimated at 15.9% (95% CI: 13.4%, 18.3%). ConclusionsUPF consumption is associated with a higher risk of gallstone disease, particularly consumption of sugar-sweetened beverages and artificially sweetened beverages. A substantial proportion of this risk is potentially mediated by obesity in younger females.