William Marcellus Howard (December 6, 1857 – July 5, 1932) was a noted jurist and politician from the American state of Georgia.

After admission to the state bar in 1880, Howard practised law in Lexington, Georgia.

He was elected as the solicitor general of Georgia's northern circuit and served in that capacity from 1884 until 1896 when he successfully ran for the United States House of Representatives.

[1] During his last few terms in the U.S. House and for several years after leaving that body, Howard served on the Board of Regents of the Smithsonian Institution (1905 through 1912) and was a trustee of the Carnegie Endowment for International Peace.

Howard cited flaws in the prosecution's case, including discrepancies in testimony and mishandling of the investigation by Atlanta police, to successfully convince Georgia Gov.