Do you need a visa to enter US?

Answer 1

If:

• you are entering only to visit,
• are a Greek Citizen,
• do not have any criminal convictions inside or outside the United States,
• have not been previously deported or overstayed a visa in the United States (or other country),
• can prove your intention to return (return ticket and itinerary),

then you do not need a visa under the Visa Waiver Program.

For other member-countries of the Visa Waiver Program along with information on qualifying under it, see the US Department of State's site on the subject:

http://travel.state.gov/visa/temp/types/types_1262.html#2