Harley Joseph Grossman (May 5, 1930 – September 5, 2003) was an American professional baseball player whose career lasted for five seasons (1949–1953) and who appeared in one Major League game as a relief pitcher for the 1952 Washington Senators.

A native of Evansville, Indiana, Grossman attended Ball State University; he stood 6 feet (1.8 m) tall and weighed 170 pounds (77 kg).

On Tuesday afternoon, April 22, 1952, at Fenway Park, the 21-year-old rookie was called into service to relieve starting pitcher Joe Haynes in the sixth inning.

Grossman surrendered an RBI single to Vern Stephens and a three-run home run to Walt Dropo, stretching Boston's lead to 9–2, before getting the third out by retiring Faye Throneberry on a ground ball.

He then returned to minor league baseball, where he compiled a 42–20 win–loss mark over his first three seasons, and he played no further after the 1953 campaign.