| William P. Hayes | |
| Order: | 27th |
| Office: | Mayor of Springfield, Massachusetts |
| Term Start: | 1900 |
| Term End: | 1901 |
| Predecessor: | Dwight O. Gilmore |
| Successor: | Ralph W. Ellis |
| Birth Date: | March 27, 1866 |
| Birth Place: | Springfield, Massachusetts |
| Office2: | Member of the Massachusetts Senate First Hampden District |
| Term Start2: | 1907 |
| Term End2: | 1907 |
| Office3: | Member of the Springfield, Massachusetts Common Council |
| Term Start3: | 1892 |
| Term End3: | 1893 |
| Death Place: | Massachusetts, U.S. |
| Alma Mater: | Boston University School of Law, 1889 |
| Profession: | Attorney |
William P. Hayes (March 27, 1866 – October 20, 1940) was an American lawyer and politician who served as the twenty seventh Mayor of Springfield, Massachusetts.
Hayes was born in Springfield, Massachusetts, on March 27, 1866, to John and Margaret Hayes.
Hays was educated at the Springfield grammar and High Schools. Hayes attended Ottawa College in Ottawa, Ontario, where he spent one year, and Boston University School of Law, from which he graduated in 1889.
Hayes was the Assistant City Assessor of Springfield in 1887 and 1888. Hayes was admitted to the Massachusetts Bar at Springfield, Massachusetts, on November 12, 1889. He was also the first Irish mayor of Springfield, Massachusetts.