William Fred Birch (August 30, 1870, Newark, New Jersey – January 25, 1946, Glen Ridge, New Jersey) was an American politician and businessman who represented New Jersey's 5th congressional district in the United States House of Representatives from 1918 to 1919.

Birch was a member of the Dover Common Council for several years and city recorder from 1904 to 1909.

Birch was elected as a Republican to the Sixty-fifth Congress to fill the vacancy caused by the death of John H. Capstick and served from November 5, 1918, to March 3, 1919, but was not a candidate for renomination in 1918.

After leaving Congress, he resumed his former manufacturing pursuits; also engaged in the fire-insurance and automobile businesses and was interested in banking.

Birch died in Glen Ridge, New Jersey on January 25, 1946, and was interred in Orchard Street Cemetery in Dover.