Tax residency

In general, where you are tax resident is decided by where you live for the majority of a tax year, so wherever you live for more than 183 days is the answer to your question.

However, it is not as easy as that and apart from the earlier advice to speak to a tax professional, there are a couple of things I can offer:

The USA is one of few countries in the world that requires all its citizens resident abroad to file a tax return with the Federal (IRS) and State.  The fact you have to do this does not mean you are a US tax resident.

There is a Tax Treaty in existence between the USA and Greece; you can download a copy from the IRS website, this link will take you straight to it.  I'd advise you to read it, then go and speak to a tax adviser.

Hope this helps.

Cynic
Expat Team