Martin Harris (May 17, 1783 - July 10, 1875) was the first financier of The Book of Mormon. He was also one of the spiritual witnesses as well as a handler of the Golden Plates.

Because he showed varying religious allegiances and fervors, Harris is often portrayed as a superstitious and religiously unstable man, but it would be unfair to deny him credit for his strengths and contributions. He was financially stable and well respected in Palmyra, New York, where he met Joseph Smith, Jr and his father's family. He never varied from his support and testimony of the Book of Mormon.

His first wife was Lucy Harris (also his first cousin), whom he married on March 27, 1808. She is generally thought to be responsible for the disappearance of the first 116 pages of scriptural manuscript dictated by Joseph Smith, Jr. to her husband. They had at least six children together and were divorced.

His second wife was Caroline Young, niece of Brigham Young, whom he married on November 1, 1836. They had seven children.

He died in Clarkston, Utah.