William Gustav Thon (February 27, 1886 – May 23, 1953) was an American politician and lawyer.

Thon practiced law in Chicago, Illinois.

Thon served in the Illinois House of Representatives from 1915 to 1923; from 1925 to 1927; from 1929 to 1933; and then from 1939 until his death in 1953.

Thon died at his home in Chicago, Illinois from a brief illness.

This article about a Member of the Illinois House of Representatives is a stub.