William Frazer Baker (1866 – December 4, 1930) was the owner of the Philadelphia Phillies of the National League from 1913 through 1930 and New York City Police Commissioner from 1909 to 1910.

For most of his tenure as the Phillies' owner, the team had only one scout, and used a flock of sheep to trim the grass at their ballpark, mockingly nicknamed "Baker Bowl" by the press in 1923.

Baker was so cheap that he sold star pitcher Grover Cleveland Alexander and catcher Bill Killefer to the Chicago Cubs in 1917 rather than increase their salary.

Within a year, the Phillies had crumbled to sixth place—the first of 14 straight seasons (and 30 of the next 31) without a winning record[citation needed] and Alexander and Killefer led the Cubs to the pennant.

Baker died of a heart attack on December 4, 1930 while attending a league meeting in Montreal and was succeeded as Phillies owner by Gerald Nugent.