Frederick William Mansfield (March 26, 1877 – November 6, 1958) was an American politician who served as the mayor of Boston, Massachusetts.

[8][9] In 1913, Mansfield was elected treasurer and receiver general of the Commonwealth of Massachusetts serving from 1914 to 1915.

[7] He took advantage of the Works Progress Administration to build the Huntington Avenue subway, a $1.715 million project the city only had to pay $539,227 for.

[13] He was not eligible to run for re-election, as Massachusetts law at the time did not allow the Mayor of Boston to serve consecutive terms.

[16] Mansfield died in St. Elizabeth's Hospital, Boston, Massachusetts, November 6, 1958.