William Harry Hallman (March 15, 1876 – April 23, 1950) was an American professional baseball player.
As an outfielder, he played for three different teams in Major League Baseball; the Milwaukee Brewers in 1901, the Chicago White Sox in 1903, and the Pittsburgh Pirates in 1906 and 1907. Additionally, he had long minor league baseball career, beginning in 1894 and ending in 1914.
Hallman died at the age of 74 in his hometown of Philadelphia, Pennsylvania, and is interred at Mount Peace Cemetery.
He is the nephew of Bill Hallman, who also played baseball at the Major League level.