William J. Morgan (December 13, 1883 – October 1983) was an American politician and lawyer who served as the 24th Attorney General of Wisconsin from 1921 to 1923.

Born in Charlesburg, Wisconsin, Morgan graduated from University of Wisconsin–Madison.

He initially worked as a lawyer in the office of Nathan Glicksman, but in 1910 started his own practice in Milwaukee.

In 1918, he started a partnership with Guy D. Goff and Frank M. Hoyt.

He announced his candidacy for the Republican nomination for state Attorney General on August 20, 1920, and won the Republican primary held on September 7, defeating Adolph Kanneberg, who had been the preferred candidate of Senator Robert M. La Follette.