William Frazer Baker (1866 – December 4, 1930) was the owner of the Philadelphia Phillies of the National League from 1913 through 1930. Baker was appointed New York City Police Commissioner in July 1909 by Mayor George B. McClellan, Jr. During his brief tenure, he was accused of interfering in gambling investigations. He resigned from his position in October 1910. In January 1913, Baker was part of a group led by his nephew, William Locke, that purchased the club. Baker was elected Team President in October 1913, following the death of Locke earlier in the year. He was at the helm two years later when the Phillies played in the 1915 World Series.
Baker was known for being extremely tight-fisted. 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 the Baker Bowl, which was named for him. Baker was so tight-fisted that he sold star pitcher Grover Cleveland Alexander to the Chicago Cubs in 1917 rather than increase his 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.
He 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.