Mason Weare Tappan (October 20, 1817 – October 25, 1886) was a New Hampshire state representative, a U.S. congressman from 1855 to 1861, a colonel during the American Civil War and the New Hampshire Attorney General.

Mason Weare Tappan
Member of the U.S. House of Representatives from New Hampshire's 2nd district
In office March 4, 1855 – March 3, 1861
Preceded by	George W. Morrison
Succeeded by	Edward H. Rollins
Member of the New Hampshire House of Representatives
In office 1853–1855
Personal details
Political party	Know Nothing
Other political affiliations	Republican
Military service
Allegiance	United States
Branch/service	Union Army
Years of service	1861
Rank	Colonel
Commands	1st New Hampshire Infantry
Battles/wars	American Civil War

He was born in Newport, New Hampshire, and grew up in Bradford. He attended private schools and the Hopkinton and Meriden academies. He studied law and was admitted to the bar in 1841 and commenced practice in Bradford.

Tappan served in the New Hampshire House of Representatives 1853 to 1855. He was elected as an American Party candidate to the Thirty-fourth Congress and reelected as a Republican to the Thirty-fifth and Thirty-sixth congresses (March 4, 1855 – March 3, 1861). While in Congress, he served as chairman, Committee on Claims (Thirty-sixth Congress). He was not a candidate for renomination in 1860.

During the Civil War, he served as colonel of the 1st New Hampshire Infantry, a three-months regiment raised in 1861 in response to President Abraham Lincoln's call to arms. He mustered out in August 1861.

Tappan died in office as the New Hampshire Attorney General at the age of 69. He is buried in Pleasant Hill Cemetery, Bradford, New Hampshire.