Thomas Jefferson Sullivan (1859 – October 13, 1909) was an Irish born catcher in Major League Baseball.

Nicknamed "Sleeper" and "Old Iron Hands",[1] Sullivan played for the National League's Buffalo Bisons, the American Association's St. Louis Brown Stockings and Louisville Eclipse, and the Union Association's St. Louis Maroons during the 1880s.

[4] After the season, Sullivan jumped to the American Association's St. Louis Brown Stockings,[5] where he played in 1882 and part of 1883.

He spent that year playing in the Eastern League for the Meriden Silvermen and Hartford Dark Blues, and in 1887, he played for the Eastern League's Danbury Hatters and the Pennsylvania State Association's Reading franchise.

His last stop was the Eastern League in 1892 before ending his professional baseball career.