Southwest Asia or Southwestern Asia (largely overlapping with the Middle East) is the southwestern portion of Asia. The term Western Asia is sometimes used in writings about the archeology and the late prehistory of the region, and in the United Nations subregion geoscheme. Unlike the Middle East, which is a vaguely-defined region generally meant to include the North African country of Egypt, Western Asia is a purely geographical term, which includes the southwestern extreme of Asia.

Southwest Asia is partly coterminous with the traditional European names the Middle East and the Near East, both of which describe the regions' geographical position in relation to Europe rather than their location within Asia. The term Western Asia has become the preferred term of use for the Middle East by international organizations (most notably the United Nations) and also in countries to the east of the region, such as India and Australia, because of the perceived Eurocentrism of the historical term Middle East. In terms of cultural and political geography, the Middle East sometimes includes North African and western South Asian countries, particularly Afghanistan, Pakistan, and Egypt.

The United Nations includes Turkey and the South Caucasus States (Armenia, Azerbaijan, and Georgia) in its Western Asian subregion, as they are almost entirely located there. However, these countries also lie in regions that straddle both Asia and Europe, and have sociopolitical ties to the latter. Turkey is located in Europe and in Asia. The Asian part of the Arab world (including Arabia proper) is called the Mashreq in Arabic.