W-8 is a form used in the United States for tax purposes, specifically for individuals who are non-resident aliens or foreign entities receiving income from U.S. sources. The purpose of the W-8 form is to establish the tax status of the recipient and to ensure appropriate withholding of taxes.

The W-8 form is provided to the payer or withholding agent, such as a financial institution or employer, to certify the foreign status of the recipient. It requires the individual or entity to provide personal information, such as name, address, and taxpayer identification number, along with details regarding their tax residency status.

There are different versions of the W-8 form, including W-8BEN for individuals, W-8BEN-E for entities, and W-8ECI for individuals or entities claiming income effectively connected with a U.S. trade or business.

By submitting a completed W-8 form, the recipient declares their eligibility for a reduced or exempt withholding tax rate under a tax treaty or establishes that no withholding tax is required.

Overall, the W-8 form serves as an important tool in the U.S. tax system to determine the appropriate tax treatment for non-resident aliens and foreign entities receiving income from U.S. sources.