Deduction may refer to:
- Deductive reasoning, inference in which the conclusion is of no greater generality than the premises
- Natural deduction, an approach to proof theory that attempts to provide a formal model of logical reasoning as it "naturally" occurs
- Tax deduction, variable tax dollars that you can subtract, or deduct, from your gross income.
- Itemized deduction, eligible expense that individual taxpayers in the United States can report on their Federal income tax returns
- Standard deduction, dollar amount that non-itemizers may subtract from their income
- Deduction (food stamps), used to calculate a household’s monthly food stamp benefit goods to help you eat