An expatriate (in abbreviated form, expat) is a person temporarily or permanently residing in a country and culture other than that of the person's upbringing or legal residence.

The word comes from the Latin ex (out of) and the Greek and Latin patria (πατριά - country), and is sometimes misspelled (either unintentionally or intentionally) as ex-patriot or short x-pat, because of its pronunciation.

The term is often used in the context of Westerners living in non-Western countries, although it is also used to describe Westerners living in other Western countries, such as Australians living in the United Kingdom, or Britons living in Spain.

Expatriate can just as well be used to describe any person living in a country other than where they hold citizenship, but is generally not used for government officials stationed in a foreign country.

During the 19th century Americans flocked to Europe -- especially to Munich and Paris, to study the art of painting. Henry James was a famous expatriate American writer from the 1870s, who adopted England as his home.

A famous group of expatriates was the so-called "Lost Generation," a term referring to American literary notables who lived in Paris from the time period which saw the end of World War I to the beginning of the Great Depression. This group included people such as Ernest Hemingway, F. Scott Fitzgerald, T. S. Eliot, Ezra Pound, and Gertrude Stein. Another famous group of expatriates was the so-called Beat Generation of American artists living in other countries during the 1950s and 1960s. This group included Allen Ginsberg, William S. Burroughs, Harold Norse, Gregory Corso and Gary Snyder.

Later generation expatriates included 50's jazz musicians such as Steve Lacy, 60's rock musician Jim Morrison, and 70's singer-songwriter Elliott Murphy.

A nickname in the UK for former expatriates who have returned to Britain is the "When I"s, or "When we"s, as they are accused of starting conversations by saying "When I was in Rhodesia" or "When we were in Singapore". Similarly, they are sometimes even viewed by their fellow citizens as foreigners, particularly their children, whose accents may seem strange to their classmates.

The children of expatriates are often considered Third Culture Kids (or TCKs) and later in life consider themselves "Adult Third Culture Kids" (or ATCKs). These children often hold passports from multiple countries, speak several different languages, and have a hard time defining where "home" is.

The difference between an expatriate and an immigrant is that immigrants (for the most part) commit themselves to becoming a part of their country of residence, whereas expatriates are usually only temporarily placed in the host country and most of the time plan on returning to their home country, so they never adopt the culture in the host country - though some may end up never actually returning, with the distinction then becoming more a matter of their own viewpoint.

While Europeans or North Americans living in the Middle East and Asia may marry local people and have children, most see no advantage in adopting citizenship of their host countries, usually because they consider their stay only temporary.

In countries like Saudi Arabia, many expatriates live on segregated compounds rather than integrate with the local population. As a result a lively community of social blogs has evolved that links the different segregated communities.

There are approximately at least 3 million to 7 million Americans living in foreign countries, roughly a half million of these are military-government personnel, yet exact estimates are difficult beyond the military personnel.