John A. Heffern (born 1953) is an American diplomat. Heffern served as the United States Ambassador to Armenia from 2011 to 2014. After being nominated on May 18, 2011 by United States President Barack Obama, Heffern was confirmed by the U.S. Senate on September 26, 2011 and sworn in as Ambassador on October 6, 2011. He was replaced by Ambassador Richard M. Mills Jr. in early 2015.