Joseph Emmett Gallagher (March 7, 1914 – February 25, 1998), nicknamed "Muscles", was an American professional baseball left fielder.

He played two seasons in Major League Baseball (MLB) for the New York Yankees, St. Louis Browns, and Brooklyn Dodgers between 1939 and 1940.

Gallagher began to climb his way up the ladder in the Yankees farm system, eventually playing for their Double-A ball club, the Kansas City Blues.

At Kansas City, Gallagher continued to show his power at the plate, leading the team with 24 home runs.

Gallagher was back-up to outfielder George Selkirk and made his MLB debut April 20, going 0–3 in the Yankees 2–0 win over the Boston Red Sox.

On June 13 of his rookie season, the Yankees traded Gallagher to the St. Louis Browns for reserve infielder Roy Hughes.