It is not uncommon for businesses expanding their operations across international borders to discover that moving employees abroad has created tax issues—and unfortunately, they often don’t discover this until they receive notice that overseas employees are noncompliant in either their Home or Host country.
When they are working outside the United States, most US citizens and permanent residents (i.e., green card holders) will be required to file income tax returns in both their Host country and in the United States. Filing two sets of returns can be a headache for the taxpayer, but it does not necessarily mean that they will be taxed twice on the income earned while working abroad.
If you have employees working outside the United States who are US citizens or permanent residents (i.e., a green card holder), these individuals will need to continue filing US tax returns to declare all of the income they earn in both the United States and their Host country. This requirement does not change if they are employed or paid from a non-US employer. Additionally, most of the tax rules that apply to taxpayers living in the United States will also apply to US persons operating overseas. The result may be that an overseas employee will be subject to tax in both the US and other jurisdictions.