The study models the impact of reduced funding from international donors, such as USAID and the Global Fund, on the household economic burden of tuberculosis in 79 low- and middle-income countries in 2025–2050. Ending USAID funding would result in an additional cost to patients of $7.5 billion (95% uncertainty interval: $6.1–8.9 billion) and 3.9 (3.1–4.6) million additional households facing catastrophic costs (above 20% of annual income). The worst-case scenario—removing all external TB funding—would result in $79.7 billion ($60.0–99.2 billion) in additional costs and 40.5 (30.9–50.7) million additional households with catastrophic costs, a 32% increase from the baseline. The impact is greatest on poor households, where more than 50% of additional disaster costs fall on the poorest 20% of households. The analysis used linked epidemiological and economic models calibrated to LMICs. Limitations include uncertainty about the costs of untreated patients and the assumptions of constant costs and uniform reduction in treatment. Funding cuts threaten progress on financial risk protection and health equity.