Thomas O. Sully (November 24, 1855 – March 15, 1939)[1] was one of the most important architects in the city of New Orleans at the end of the 19th century.

[2] Sully's works include the Hennen Building addition and Poplar Grove Plantation (1884) in Port Allen, Louisiana.

[4][5][6] He was named after his great uncle, portrait painter Thomas Sully (1783–1872).

[7] Sully lived at 4010 St. Charles Avenue (1886) in a house he built.

A boating aficionado, Sully was commodore of the Southern Yacht Club in New Orleans for two terms, was photographed on his yacht Helen, and designed boats.