Robert McClelland Barr (December, 1856 – March 11, 1930) was a Major League Baseball pitcher. He also made some appearances as an outfielder, first baseman, and third baseman. Barr played for the Pittsburgh Alleghenys, Washington Nationals, Indianapolis Hoosiers, and Rochester Broncos, all of the American Association. He also played for the National League teams the Washington Nationals and New York Giants.