Sixteen nations contributed combat troops to the UN Command during the Korean War. The force was created after North Korea invaded South Korea on 25 June 1950, with the United States serving as the executive agent for a unified command authorized by the UN Security Council.
The 16 combatant contributors were the United States, United Kingdom, Australia, Canada, France, New Zealand, the Netherlands, the Philippines, Turkey, Thailand, South Africa, Greece, Belgium, Luxembourg, Ethiopia, and Colombia. The United States supplied the largest contingent, while the other countries contributed formations ranging from brigades and battalions to air and naval units.
The number is often confused with the broader total of countries that supported the UN effort. Six additional nations provided medical or humanitarian assistance, and other countries supplied various forms of logistical or political support. Thus, 16 refers specifically to nations that sent combat troops, not every nation associated with the Korean War effort.