The 4th Wisconsin Cavalry Regiment was a volunteer cavalry regiment that served in the Union Army during the American Civil War.

Earlier in the war, it had been organized as the 4th Wisconsin Infantry Regiment.

The regiment mustered out of Federal service at Brownsville, Texas, on May 2, 1866, and disbanded at Madison, Wisconsin, on June 19, 1866.

The 4th Wisconsin Cavalry initially recruited 1,047 officers and men.

[1] The regiment suffered 11 officers and 106 enlisted men killed or died from wounds in action, and 3 officers and 311 enlisted men who died of disease, for a total of 431 fatalities.