The tax situation for U.S. territories is complex and varies between them. Here's a brief overview:

Puerto Rico and U.S. Virgin Islands:

Residents generally do not pay federal income tax on local income. They do pay federal payroll taxes (Social Security and Medicare). They have their own tax systems.

Guam and Northern Mariana Islands:

Have a "mirror" tax system that parallels the U.S. federal tax system. Residents pay taxes to the territorial government instead of to the U.S. federal government.

American Samoa:

Has its own tax system. Residents generally do not pay federal income taxes.

However, there are exceptions:

Federal employees in these territories generally pay federal income tax. Residents with income sources from the U.S. mainland may need to pay federal taxes on that income. Some residents may need to file U.S. tax returns under certain circumstances.

It's important to note that while residents of these territories may not pay federal income taxes in many cases, they also don't have full representation in Congress and can't vote in U.S. presidential elections (though they may participate in primary elections).