Walter Harriman (April 8, 1817 – July 25, 1884) was an American minister, merchant, soldier, and politician who served as the 31st governor of New Hampshire.

On July 23, 1866, the United States Senate confirmed President Andrew Johnson's May 31, 1866, nomination of Harriman for appointment to the grade of brevet brigadier general of volunteers to rank from March 13, 1865.

The following year, he resigned as a minister and opened a store in Warner, partnering with John S. Pillsbury, a future governor of Minnesota and industrialist.

In 1853, Harriman returned to politics and served as state treasurer until 1854 when he moved to Washington, D.C., to take the role as Clerk of the Pension Office, a patronage position which he held until 1856.

)[3] He interrupted his military service, resigning on June 26, 1863,[2] to run as a War Democrat in the 1863 New Hampshire gubernatorial campaign.

He siphoned off enough regular Democratic votes to give the election to Republican candidate Joseph A. Gilmore.

He was very concerned with the education of post-war citizens of the state, and he signed an act creating teacher institutes.