William D. Reilich (born March 17, 1957) is an American politician best known for having served as a New York State Assemblyman.

In 1997 he was picked by the Republican members of the county legislature, to succeed John T. Auberger who resigned to become Greece town supervisor.

He also served on the board of the County of Monroe Industrial Development Agency (COMIDA).

Reilich successfully defended his county legislative seat in 1999[5] and ran unopposed in 2001.

[8] In Town of Greece v. Galloway, the United States Supreme Court ruled in favor of the practice of opening town meetings with a prayer—a practice Reilich continued from his predecessor.