I do not earn any income in the United States and am living off of a foreign-sourced grant. I also do not live in the United States. Do I need to file taxes?

[gmouzoun]

I have been living in a different country for the past 5 years. I do not have a professional income. Do i still need to file taxes?

[jtax]

If you are a US citizen the US taxes your world-wide income no matter where you life. If you make enough you need to file a US return. There are various things (treaty provisions and the foreign tax credit - FTC) that give you credit for any foreign tax you paid and will usually reduce or eliminate any US tax due for a US Citizen living overseas without a lot of US income.

To see if you made enough to have a filing requirement, see

https://www.irs.gov/individuals/check-if-you-need-to-file-a-tax-return