Arnold A. Chacón (born 1956) is an American career diplomat who served as acting United States Ambassador to Canada in 2021.

A career U.S. Foreign Service officer, he has served in a number of leadership positions in Latin America and Europe, including Deputy Chief of Mission in Madrid, Spain.

He has led initiatives to promote free and fair elections, advance respect for human rights, and support the rule of law.

While ambassador, Chacón also directed crisis management operations, worked with international partners to combat human trafficking, and advanced regional free trade agreements.

[3] He was then detailed from the Department of State to the National Defense University as Senior Vice President.