There are two significant people named William H. Avery: a former Governor of Kansas, and an influential engineer.

William Henry Avery (born August 11, 1911) was governor of the U.S. state of Kansas from 1965 to 1967. William H. Avery graduated from the University of Kansas in 1934. He was a member of the Wakefield, Kansas School board, and served in the Congress for the Republican Party. After losing the Governorship to Robert Docking in the election of 1966 he attempted but failed to win a seat in the Senate. After retiring from politics he worked for Clinton Oil Company, and became president of Real Petroleum . He is the oldest living governor of Kansas.

William H. Avery (1913–June 26, 2004) was an influential aeronautics engineer. He is most remembered for designing the propulsion mechanisms known as the ramjet, and for heading the Ocean Thermal Energy Conversion program which generates electricity from the temperature differential between shallow and deep ocean water.