| William J. Gannon | |
| Office: | Member of the Iowa House of Representatives |
| Term Start: | 1965 |
| Term End: | 1971 |
| Birth Date: | 9 July 1937 |
| Birth Place: | Mingo, Iowa, United States |
| Party: | Democratic |
| Occupation: | farmer |
William J. Gannon (born July 9, 1937) was an American politician in the state of Iowa.
Gannon was born in Mingo, Iowa. He was a farmer. He served in the Iowa House of Representatives from 1965 to 1971 as a Democrat.[1]