Tourism is travel for pleasure; also the practice and theory of touring, the business of attracting, accommodating, and entertaining tourists, and the business of operating tours. Tourism may be international, or within the traveller's country. The World Tourism Organization defines tourism more generally, in terms which go "beyond the common perception of tourism as being limited to holiday activity only", as people "staying in and travelling to places outside their usual environment for not more than one consecutive year for leisure, business and other purposes".Tourism can be domestic or international, and international tourism has both outgoing and incoming implications on a country's balance of payments. Today, tourism is a huge source of income for many countries, and affects the economy of both the source and host countries, in some cases being of vital importance.

Tourism brings in huge amounts of income into a local economy in the form of payment for goods and services needed by tourists, accounting for 30% of the world's trade of services, and 6% of overall exports of goods and services. It creates opportunities for employment in the service sector of the economy associated with tourism.The service industries which benefit from tourism include transportation services, such as airlines, cruise ships, and taxicabs; hospitality services, such as accommodations, including hotels and resorts; and entertainment venues, such as amusement parks, casinos, shopping malls, music venues, and theatres. This is in addition to goods bought by tourists, including souvenirs, clothing and other supplies.