A document published by the Internal Revenue Service that provides guidance to businesses who pay income to foreign workers. The document applies to tax withholding for foreign individuals, businesses, trusts and organizations. Publication 515 outlines the personnel responsible for withholding tax (referred to as withholding agents), the type of taxes subject to withholding and how withholding is to be conducted.

Tax withheld from a foreign worker is referred to as non-resident alien, or NRA, withholding, and is different from regular income tax withholding. Unlike resident aliens and U.S. citizens who are taxed on worldwide income, non-resident aliens are subject to taxation on income from U.S. work. The typical withholding percentage is 30%, although exemptions are allowed, which can lower this percentage.