Which are the Visa Waiver countries for the USA?

At present, to be eligible for the Visa Waiver Program (VWP), you must be a citizen of a country that has been designated by the U.S. Secretary of Homeland Security, in consultation with the Secretary of State, as a “program country”. Note that if you are a permanent resident of a program country but are not a citizen, then you do not qualify for the visa waiver.
Currently there are 38 countries that meet the criteria of Section 217(c) of the Immigration and Nationality Act (Title 8 U.S.C § 1187), which includes passport security, a non-immigrant visa refusal rate of 3% or less, and ongoing compliance with the immigration law of the U.S.
The 38 countries and territories that are part of the Visa Waiver Program are:
Andorra

Andorra

Australia

Australia

Austria

Austria

Belgium

Belgium

Brunei

Brunei

Chile

Chile

Czech Republic

Czech Republic

Denmark

Denmark

Estonia

Estonia

Finland

Finland

France

France

Germany

Germany

Greece

Greece

Hungary

Hungary

Iceland

Iceland

Ireland

Ireland

Italy

Italy

Japan

Japan

Latvia

Latvia

Liechtenstein

Liechtenstein

Lithuania

Lithuania

Luxembourg

Luxembourg

Malta

Malta

Monaco

Monaco

Netherlands

Netherlands

New Zealand

New Zealand

Norway

Norway

Portugal

Portugal

San Marino

San Marino

Singapore

Singapore

Slovakia

Slovakia

Slovenia

Slovenia

South Korea

South Korea

Spain

Spain

Sweden

Sweden

Switzerland

Switzerland

Taiwan* Citizens with Taiwanese national ID number only

Taiwan* Citizens with Taiwanese national ID number only

United Kingdom* Only British citizens

United Kingdom* Only British citizens