Thomas H. Cahill (October 1868 – December 25, 1894) was an American professional baseball player who played from 1888 to 1894.

He played one season in Major League Baseball and had a career batting average of .253 with 109 hits, 17 doubles, 7 triples, 3 home runs, 44 RBIs, and 38 stolen bases.

[3] He left the University of Pennsylvania School of Medicine in 1891 to play professional baseball full-time, but planned on returning to his studies and eventually becoming a doctor.

The next season, Cahill played with the New Haven, Connecticut, baseball club of the Atlantic Association.

[5] Cahill was first in the majors in stolen bases amongst fellow rookies (tied with Tommy Dowd), and was second in the league (first in the American Association) in doubles.