Thomas Sloo Jr. (April 5, 1790 – January 17, 1879) was an American politician and merchant from Kentucky. Orphaned, Sloo moved to Cincinnati, Ohio, to support his siblings and made a fortune operating a store. However, he lost it all in the Panic of 1819 and settled in Illinois. He quickly regained prosperity after organizing McLeansboro, Illinois and was soon elected to the Illinois Senate. Sloo was an unsuccessful candidate for Governor of Illinois in 1826. Crestfallen, Sloo moved to New Orleans, Louisiana to trade commissions. After a brief stay in Havana, Cuba, where he founded a gas company, Sloo returned to New Orleans and served as city treasurer and president of the Sun Mutual Insurance Company.