Hans F. Loeser (September 28, 1920 – May 15, 2010) was an American lawyer whose activism during the Vietnam War earned him the enmity of Richard Nixon.
Born in Germany, Loeser served in the United States Army, 1942–1947.
He graduated magna cum laude in 1950 and began a long career at Foley Hoag in Boston.
His work as Chair of the Boston Lawyers' Vietnam Committee landed him on the master list of Nixon political opponents.
He was then a long-term member emeritus of the Lawyers' Committee for Civil Rights Under Law in Boston.