Mulford Quickert Sibley (1912–1989) was a professor of political science at the University of Minnesota.

He was a controversial figure because he advocated positions such as socialism and pacifism at a time (the McCarthy era of the 1950s) when these were highly unpopular.

[1] A prolific author and essayist, Sibley wrote extensively on pacifism, utopianism, and civil disobedience.

A collection of his papers at the Minnesota Historical Society includes correspondence, literary works, and teaching materials.

[2] Both in his classes and at political rallies, Sibley often spoke out against the Vietnam War.