William N. Belter (July 7, 1926 – December 12, 1999) was an American lawyer, businessman, and politician.
He represented Green Lake and Waushara counties in the Wisconsin State Assembly from 1953 to 1957.
He was also the attorney for Ed Gein during his 1968 trial in Waushara County for the murder of Bernice Worden.
In 1982, when it seemed no other Republican was willing to challenge incumbent Bronson La Follette, the party attempted to recruit Belter to run for Wisconsin Attorney General.
He consented to the run, but the Party ultimately did not collect enough signatures to put his name on the ballot, and he received a small number of write-in votes in the election.