| William H. MacInnis | |
| Office: | 10th Mayor of Pittsfield, Massachusetts |
| Term Start: | 1908 |
| Term End: | 1910 |
| Predecessor: | Allen H. Bagg |
| Successor: | Kelton B. Miller |
| Office2: | Member of the Massachusetts Senate Berkshire District |
| Term Start2: | 1904 |
| Term End2: | 1906 |
| Birth Date: | November 22, 1860 |
| Birth Place: | Cape Breton, Nova Scotia |
| Death Place: | Dalton, Massachusetts |
| Party: | Democratic |
| Profession: | Cloak and Suit buyer |
William Henry Havelock MacInnis (November 22, 1860 – November 14, 1928)[1] was an American politician who served as a member of the Massachusetts Senate and Mayor of Pittsfield, Massachusetts.