William N. Belter (July 7, 1926 – December 12, 1999) was an American, lawyer, businessman, and politician.
Born in Wausau, Wisconsin, Belter graduated from high school in Wautoma, Wisconsin. He then received his bachelor's degree from University of Wisconsin–Madison and his law degree from University of Wisconsin Law School. He practiced law in Wautoma, Wisconsin. He was a real estate broker and a bank director. Belter was a justice of the peace and was district attorney for Waushara County, Wisconsin from 1968 to 1977. He was also the attorney for Ed Gein during his 1968 trial in Waushara County, Wi for the murder of Bernice Worden. (Judge Robert H Gollmar 1968). Belter also served in the Wisconsin State Assembly, as a Republican from 1953 to 1957.