Military advisors, or combat advisors, are soldiers sent to foreign nations to aid that nation with its military training, organization, and other various military tasks. These soldiers are often sent to aid a nation without the potential casualties and political ramifications of actually mobilizing military forces to aid a nation.

European advisors during the American Revolution

The French Marquis de Lafayette and the German/Prussian Baron von Steuben offered key assistance to the Continental Army during the American Revolutionary War.

US advisors in Vietnam

In the early 1960s, elements of the U.S. Army Special Forces and Echo 31 went to South Vietnam as military advisors to train and assist the South Vietnamese Army (ARVN) for impending actions against the North Vietnamese People's Army of Vietnam (PAVN). United States Marines also filled a significant role as advisors to Vietnamese forces.

US advisors during the "War on Terror"

Combat advisors served on the front-lines of the U.S. War on Terror. They are designated as Embedded Training Teams (ETTS) in Afghanistan and Military Transition Teams (MTTs) in Iraq. These soldiers and Marines live with their Afghan and Iraqi counterparts (often in very austere and stoic conditions) in remote combat outposts often a great distance away from any U.S. or coalition support.