What's the Difference Between an ITIN and a Social Security Number?

An ITIN (Individual Taxpayer Identification Number) and a Social Security Number (SSN) are both nine-digit numbers used for tax purposes, but they serve different purposes and come from different agencies. An SSN is issued by the Social Security Administration and can be used for both tax filing and to access Social Security benefits, employment authorization, and many government programs. An ITIN is issued by the IRS specifically for tax filing and is only available to people who are not eligible for an SSN, including certain nonresident and resident aliens, their spouses, and their dependents. Having an ITIN does not authorize a person to work in the United States or qualify them for Social Security benefits. Both numbers allow the IRS to track income and filings, but they represent entirely different legal and immigration statuses.