John Joseph Cavanaugh (June 5, 1900 – January 14, 1961) was an American Major League Baseball third baseman.

He played in one game for the Philadelphia Phillies on July 7 during the 1919 Philadelphia Phillies season, and was the first player born in the 1900s to appear in a Major League Baseball game.

[1] Following his one game played during the 1919 season as a 19-year-old, Cavanaugh played in parts of 3 minor league seasons.

He spent 1921 and 1922 with the Reading Aces of the International League and 1924 with the Wilkes-Barre Barons of the New York-Penn League.

This biographical article relating to a baseball third baseman is a stub.