Tom O'Brien (c. 1851 − September 29, 1904) was an American confidence man and swindler during the late 19th century. He was popularly known as "King of the Banco Men", along with other prominent tricksters such as Joseph "Hungry Joe" Lewis and Charles P. Miller, and organized countless banco and confidence schemes throughout the United States, especially in New Orleans, Chicago and New York, as well as in Europe. He often partnered with a number of confidence and banco men such as Lon Ludlam, Red Adams, Frank Smith, Pete Carlisle, Ed Ray, Red Austin, Charley Hinnell, "Hungry Joe" Lewis and Reed Waddell. He later shot and killed Waddell in an argument over money following a scheme they had run in Paris, France.