The 128th Maine Senate had 35 members each elected to two-year terms in November 2016. The first regular session was sworn in on December 6, 2016.
The 128th Senate party composition was:
| Position | Name | Party | Residence | County | |
|---|---|---|---|---|---|
| Waldo | |||||
| Garrett Mason | Androscoggin | ||||
| Assistant Majority Leader | Penobscot | ||||
| Aroostook | |||||
| Assistant Minority Leader | Androscoggin |
| District | Senator | Party | Municipality | County | |
|---|---|---|---|---|---|
| 1 | Troy Jackson | Democrat | Allagash | Aroostook | |
| 2 | Michael E. Carpenter | Democrat | Houlton | Aroostook | |
| 3 | Rodney Whittemore | Republican | Skowhegan | Somerset | |
| 4 | Paul T. Davis | Republican | Sangerville | Piscataquis | |
| 5 | James Dill | Democrat | Old Town | Penobscot | |
| 6 | Joyce Maker | Republican | Calais | Washington | |
| 7 | Brian Langley | Republican | Ellsworth | Hancock | |
| 8 | Kimberly Rosen | Republican | Bucksport | Hancock | |
| 9 | Geoffrey Gratwick | Democrat | Bangor | Penobscot | |
| 10 | Andre Cushing III | Republican | Hampden | Penobscot | |
| 11 | Michael Thibodeau | Republican | Winterport | Waldo | |
| 12 | David Miramant | Democrat | Camden | Knox | |
| 13 | Dana Dow | Republican | Waterboro | Lincoln | |
| 14 | Shenna Bellows | Democrat | Manchester | Kennebec | |
| 15 | Roger Katz | Republican | Augusta | Kennebec | |
| 16 | Scott Cyrway | Republican | Benton | Kennebec | |
| 17 | Tom Saviello | Republican | Wilton | Franklin | |
| 18 | Lisa Keim | Republican | Dixfield | Oxford | |
| 19 | James Hamper | Republican | Oxford | Oxford | |
| 20 | Eric Brakey | Republican | Auburn | Androscoggin | |
| 21 | Nate Libby | Democrat | Lewiston | Androscoggin | |
| 22 | Garrett Mason | Republican | Lisbon | Androscoggin | |
| 23 | Eloise Vitelli | Democrat | Topsham | Sagadahoc | |
| 24 | Brownie Carson | Democrat | Brunswick | Cumberland | |
| 25 | Cathy Breen | Democrat | Falmouth | Cumberland | |
| 26 | G. William Diamond | Democrat | Windham | Cumberland | |
| 27 | Ben Chipman | Democrat | Portland | Cumberland | |
| 28 | Mark Dion | Democrat | Portland | Cumberland | |
| 29 | Rebecca Millett | Democrat | Cape Elizbath | Cumberland | |
| 30 | Amy Volk | Republican | Scarborough | Cumberland | |
| 31 | Justin Chenette | Democrat | Saco | York | |
| 32 | Susan Deschambault | Democrat | Biddeford | York | |
| 33 | David Woodsome | Republican | Waterboro | York | |
| 34 | Ronald F. Collins | Republican | Wells | York | |
| 35 | Dawn Hill | Democrat | York | York |