The Visa Waiver Program allows you to enter the U.S. without a visa and stay up to 90 days. There are some important conditions for eligibility, however. First, you must be entering the U.S. as a tourist or for a short business trip. Second, you must have a valid passport. Third, you must be the citizen or subject of one of these countries: Andorra, Australia, Austria, Belgium Brunei, Czech Republic, Denmark, Estonia, Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Japan, Republic of Korea, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Monaco, the Netherlands, New Zealand, Norway, Portugal, San Marino, Singapore, Slovakia, Slovenia, Spain, Sweden, Switzerland. All others must have a visa in order to enter the United States.