An international airport is an airport typically equipped with customs and immigration facilities to handle international flights with other countries.

These airports are usually large and often have large runways and facilities adequate to handle the large aircraft that are commonly used for international or intercontinental routes. International airports often host domestic flights (flights within the country's borders) in addition to international flights. In many of the small countries, the majority of airports are international. In certain countries, however, there is a subcategory of limited international airports that serve international flights, but are limited to short-haul destinations (often due to geographic factors) or are mixed (civil and military) airports.

Many airports with frequent scheduled international flights have the word "International" in their official names, but others, including large airports such as London Heathrow Airport, do not. On the other hand, some airports that call themselves international airports, especially in small cities in the United States, although there are not really scheduled international passenger flights as they have such facilities with customs and immigration offices for charter, cargo and general aviation flights.

At many of these airports, customs and immigration services are only available for a few hours. An example of these airports is Gerald R. Ford International Airport in Grand Rapids, Michigan.

Other airports that have previously served international flights now primarily serve domestic flights (international traffic has been moved to a new, larger airport in the area), but maintain the "international" designation in their name.

Examples of this are:.

Many international airports also serve as home bases, or places where flights with stopovers can land and passengers can board the plane. International airports often have many airlines represented, and many of these are usually foreign.