John Wesley Gaines was an American politician and a member of the United States House of Representatives for the 6th congressional district of Tennessee.
He was born on August 24, 1860 in Wrecoe, near Nashville, Tennessee in Davidson County. He attended private and public schools, in which he also taught. He studied law at home, studied medicine, and graduated from the University of Nashville. He graduated from the Vanderbilt University in Nashville, Tennessee in 1882. He never practiced medicine, but the day after graduation he resumed the study of law. He was admitted to the bar in 1884 and commenced practice in Nashville in 1885.
He was elected as a Democrat to the Fifty-fifth and the five succeeding Congresses. He served from March 4, 1897 to March 3, 1909. He was an unsuccessful candidate for re-election in 1908 to the Sixty-first Congress. He practiced law in Nashville, Tennessee, where he died on July 4, 1926. He was interred in Mount Olivet Cemetery.