John Blair (September 13, 1790 – July 9, 1863) was an American politician who represented Tennessee in the United States House of Representatives.
He was born in Blairs Mill near Jonesborough, Tennessee and attended Martin Academy and graduated from Washington College in Tennessee in 1809. He studied law, was admitted to the bar in 1813, and practiced. He served as a member of the Tennessee House of Representatives between 1815 and 1817 and as a member of the Tennessee Senate between 1817 and 1821.
Blair was elected as a Jacksonian Republican to the Eighteenth Congress and re-elected as a Jacksonian to the Nineteenth through Twenty-third Congresses. He served as a U.S. Representative from March 4, 1823 to March 3, 1835. During the Twentieth Congress, he was chairman of the U.S. House Committee on Expenditures in the State Department. He was an unsuccessful candidate for re-election to the Twenty-fourth Congress in 1834.
John Blair retired to private life, then again became a member of the Tennessee House of Representatives in 1849 and 1850. He resumed the practice of law, died in Jonesboro, Tennessee and was interred in Old Cemetery.