Clayton Kirk Slack (February 23, 1896 – March 1, 1976) was a soldier in the United States Army who received the Medal of Honor for his actions during World War I.

[1] Clayton Slack joined the United States Army from Madison, Wisconsin in September 1917.

[3] As a private, he was cited for single-handedly clearing out a German machine gun nest resulting in 10 prisoners and the capture of 2 machine-guns on October 8, 1918, in the Meuse–Argonne offensive, the biggest battle of World War I involving American troops.

Slack noticed several German troops and charged at them with his rifle and bayonet telling them to "put their hands up".

Slack, upon his own initiative, rushed them with his rifle and, single-handed, captured 10 prisoners and 2 heavy-type machineguns, thus saving his company and neighboring organizations from heavy casualties.