John T. Mills was an American lawyer who served as a Supreme Court Justice for the Republic of Texas.
His family settled in Beaufort County, South Carolina, where he studied law before moving to Clarksville, Republic of Texas, in 1837.
From 1839 to 1845 he served three consecutive terms as an associate justice of the Supreme Court in the Third, Seventh, and Eighth Judicial Districts. After Texas was admitted to the Union, he served as a judge for the state in various district courts from 1846 to 1850. In 1849, he ran on the Democratic ticket for Governor, but was not elected.
John Mills died in Marshall, Texas, and is buried in the Marshall Cemetery there.