The 15th Wisconsin Infantry Regiment was a volunteer infantry regiment that served in the Union Army during the American Civil War.

The regiment was organized at Madison, Wisconsin, and mustered into federal service January 31, 1862.

The regiment was mustered out of service by company between December 1, 1864, and February 13, 1865.

[4] The 15th Wisconsin Volunteer Regiment was a participant in a number of major battles conducted by the Union Army during the Civil War.

[5] The 15th Wisconsin suffered eight officers and 86 enlisted men who were killed in action or who later died of their wounds, plus another one officer and 241 enlisted men who died of disease, for a total of 336 fatalities.