Western Asia, West Asia, Southwest Asia or Southwestern Asia are terms that describe the westernmost portion of Asia. The terms are partly coterminous with the Middle East, which describes a geographical position in relation to Western Europe rather than its location within Asia. Due to this perceived Eurocentrism, international organizations such as the United Nations, have replaced Middle East and Near East with Western Asia. This region and Europe are collectively referred to as Western Eurasia.

The world's earliest civilizations developed in Western Asia. For most of the last three millennia, the region has been united under one or two powerful states; each one succeeding the last, and at times, eastern and western based polities. The main states in this regard were the Assyrian Empire, the Babylonian Empire, the Achaemenid Empire, the Seleucid Empire, the Parthian Empire, the Roman Empire, the Sassanid Empire, the Byzantine Empire, the Umayyad Caliphate, the Abbasid Caliphate, the Safavid Empire, and the Ottoman Empire.