Thomas Andrew Osborn (October 26, 1836 – February 4, 1898) was an American lawyer, politician, and diplomat.

In 1856, he began to study law under a Meadville judge and was admitted to the Michigan bar in 1857.

[1] In November 1857, Osborn moved to Lawrence, Kansas, where he became a compositor for the Herald of Freedom.

The following year, Osborn was practicing law in Elwood, Kansas, and was known to be a Republican and Free-State supporter.

[3] In 1892, he was put forth as a primary challenger to Kanza Indian, and attorney, Charles Curtis, who later became Vice President of the United States.