The 1968 United States Senate elections were elections for the United States Senate. Held on November 5, the 34 seats of Class 3 were contested in regular elections. They coincided with the presidential election of the same year. The Republicans picked up five net seats in the Senate. This saw Republicans win a Senate seat in Florida for the first time since Reconstruction.
Republicans would gain another seat after the election when Alaska Republican Ted Stevens was appointed to replace Democrat Bob Bartlett, reducing Democrats' majority to 57–43.
This is the earliest round of Senate elections in which a first-elected member is still alive (Bob Packwood, R-OR).
Results summary
{| style="width:50em; text-align:center"
|+ ↓
|- style="color:white"
| style="background:; width:58%" | 58
| style="background:; width:42%" | 42
|-
| <span style="color:">Democratic</span>
| <span style="color:">Republican</span>
|}
{| class=wikitable style=text-align:center
|- valign=bottom
! rowspan=2 colspan=2 | Parties
| style="background-color:" |
| style="background-color:" |
| style="background-color:" |
| style="background-color:" |
! rowspan=2 | Total
|- valign=bottom
! Democratic
! Republican
! Conservative
! Other
|-
! colspan=2 | Last elections (1966)
| | 64
| 36
| 0
| 0
! 100
|-
! colspan=2 | Before these elections
| | 63
| 37
| 0
| 0
! 100
|-
! colspan=2 style="background:#bbb" | Not up
| | 40
| 26
| 0
| 0
! 66
|-
| colspan=100 |
|-
! colspan=2 style="background:#bbb" | Up<br />
| | 23
| 11
| 0
| 0
! 34
|-
| colspan=100 |
|-
! colspan=2 style="background:#ccc" | Incumbent retired
| 3
| 3
| —
| —
! 6
|-
! rowspan=3 |
!
| 1
| | 2
| —
| —
! 3
|-
!
| colspan=2 | 1 Republican replaced by 1 Democrat<!--IA--><br />2 Democrats replaced by 2 Republicans<!--AZ, FL-->
| —
| —
! 3
|-
! Result
! 2
! | 4
! 0
! 0
! 6
|-
! colspan=2 style="background:#ccc" | Incumbent ran
| | 20
| 8
| —
| —
! 28
|-
! rowspan=5 |
!
| | 13
| 7
| —
| —
! 20
|-
!
| colspan=2 | 4 Democrats replaced by 4 Republicans<!--MD, OK, OR, PA-->
| —
| —
! 4
|-
!
| | 2<!--AK, MO-->
| 0
| —
| —
! 2
|-
!
| colspan=2 | 1 Republican replaced by 1 Democrat<!--CA--><br />1 Democrat replaced by 1 Republican <!--OH-->
| —
| —
! 2
|-
! Result
! | 16
! 12
! 0
! 0
! 28
|-
| colspan=100 |
|-
! colspan=2 | Total elected
! | 18
! 16
! 0
! 0
! 34
|-
! colspan=2 | Net gain/loss
| 5
| | 5
|
|
! 5
|-
! colspan=2 style="background:#ccc" | Nationwide vote
| | 24,976,660
| 23,588,832