This paper analyzes presidential candidate Donald Trump’s tax proposal. His plan would significantly reduce marginal tax rates on individuals and businesses, increase standard deduction amounts to nearly four times current levels, and curtail many tax expenditures. His proposal would cut taxes at all income levels, although the largest benefits, in dollar and percentage terms, would go to the highest-income households. The plan would reduce federal revenues by $9.5 trillion over its first decade before accounting for added interest costs or considering macroeconomic feedback effects. The plan would improve incentives to work, save, and invest. However, unless it is accompanied by very large spending cuts, it could increase the national debt by nearly 80 percent of gross domestic product by 2036, offsetting some or all of the incentive effects of the tax cuts.