U.S. House seat for Massachusetts's 9th congressional district. Representatives serve two-year terms.

3 candidates filed, 2 active for the 2026 House election in Massachusetts District 9. Party primary on Sep 1, 2026. General election on Nov 3, 2026.
| Year | Winner | Result | Runner-Up | Total Votes |
|---|---|---|---|---|
| 2024 | William R. Keating D | 56.5% | 445,753 | |
| 2022 | William R Keating D | 59.2% | 334,170 | |
| 2020 | William R Keating D | 61.3% | 424,240 | |
| 2018 | Bill Keating D | 59.4% | 323,810 | |
| 2016 | William R Keating D | 55.8% | 379,484 | |
| 2014 | William R Keating D | 55.0% | 255,384 | |
| 2012 | William R Keating D | 58.8% | 361,940 | |
| 2010 | Stephen F Lynch D | 68.4% | 229,608 | |
| 2008 | Stephen F Lynch D | 100.0% | 242,166 | |
| 2006 | Stephen F Lynch D | 78.2% | 216,534 | |
| 2004 | Stephen F Lynch D | 100.0% | 218,167 | |
| 2002 | Stephen F Lynch D | 100.0% | 168,055 | |
| 2000 | John Joseph Moakley D | 77.6% | 248,690 | |
| 1998 | John Joseph Moakley D | 100.0% | 150,667 | |
| 1996 | John Joseph Moakley D | 72.2% | 238,088 |