William Augustus Ayres (April 19, 1867 – February 17, 1952) was a Democratic member of the U.S. House of Representatives from Kansas and a Federal Trade Commissioner.

He attended the common schools and Garfield University in Wichita, Kansas.

He was admitted to the bar in 1893 and commenced practice in Wichita, Kansas.

Ayres was elected as a Democrat to the Sixty-fourth, Sixty-fifth, and Sixty-sixth Congresses.

He was elected to the Sixty-eighth and to the five succeeding Congresses and served until his resignation effective August 22, 1934, having been appointed a member of the Federal Trade Commission on June 30, 1934, in which capacity he served until his death in Washington, D.C., in 1952.