Class III terms run from the beginning of the 115th Congress on January 3, 2017, to the end of the 117th Congress on January 3, 2023. Senators in Class III were elected to office in the November 2016 general election, unless they took their seat through appointment or special election.
| Bennet, Michael F. (D-CO) |
| Blumenthal, Richard (D-CT) |
| Cortez Masto, Catherine (D-NV) |
| Duckworth, Tammy (D-IL) |
| Hassan, Margaret Wood (D-NH) |
| Kelly, Mark (D-AZ) |
| Leahy, Patrick J. (D-VT) |
| Murray, Patty (D-WA) |
| Padilla, Alex (D-CA) |
| Schatz, Brian (D-HI) |
| Schumer, Charles E. (D-NY) |
| Van Hollen, Chris (D-MD) |
| Warnock, Raphael G. (D-GA) |
| Wyden, Ron (D-OR) |
| Blunt, Roy (R-MO) |
| Boozman, John (R-AR) |
| Burr, Richard (R-NC) |
| Crapo, Mike (R-ID) |
| Grassley, Chuck (R-IA) |
| Hoeven, John (R-ND) |
| Johnson, Ron (R-WI) |
| Kennedy, John (R-LA) |
| Lankford, James (R-OK) |
| Lee, Mike (R-UT) |
| Moran, Jerry (R-KS) |
| Murkowski, Lisa (R-AK) |
| Paul, Rand (R-KY) |
| Portman, Rob (R-OH) |
| Rubio, Marco (R-FL) |
| Scott, Tim (R-SC) |
| Shelby, Richard C. (R-AL) |
| Thune, John (R-SD) |
| Toomey, Patrick J. (R-PA) |
| Young, Todd (R-IN) |
Article I, section 3 of the U.S. Constitution mandates the Senate's class structure.
Amendment XVII (1913) provides for direct election of Senators.
