if i buy a cell phone from another country(usa) will it work in mine(greece)

if i buy a cell phone from another country(usa) will it work in mine(greece)?
I want to buy iphone from apple store because it is much cheaper than in my country... but i don't know if it will work....
Cell Phones & Plans - 2 Answers
Random Answers, Critics, Comments, Opinions :
1 :
No, it will not because it's locked to AT&T.
2 :
if ATT has coverage in greece, it will work