Francis John Fennelly (February 18, 1860 – August 4, 1920) was a 19th-century Major League Baseball shortstop.

He played his entire career for American Association teams: the Washington Nationals (1884), Cincinnati Red Stockings (1884–1888), Philadelphia Athletics (1888–1889), and Brooklyn Gladiators (1890).

In his rookie season of 1884 he hit .311, good for eighth in the league, and his .367 on-base percentage ranked fourth.

The best team he ever played for was the 1887 Red Stockings, who had a record of 81–54 (.600) and finished second in the league, 14 games behind the St. Louis Browns.

Fennelly died and was buried in his hometown of Fall River, Massachusetts at the age of 60.