William Willis Garth (October 28, 1828 – February 25, 1912) was an American politician.

During the Civil War, he served as a lieutenant colonel on the staff of General James Longstreet in the Confederate Army.

Garth was elected in 1876 as a Democratic representative to the 45th Congress, but was defeated for reelection in 1878.

He resumed the practice of law, and died in Huntsville, Alabama on February 25, 1912.

This article incorporates public domain material from the Biographical Directory of the United States Congress