List of special elections to the California State Senate
Special elections to the California State Senate are called by the Governor of California when a vacancy arises within the State Senate. Most special elections are conducted in two rounds. The first is an open primary and the candidate with the most votes must have a majority of the votes plus one to win the seat. If no candidate wins a majority, a second round is held with the two top candidates regardless of party.
Recall elections, the process by which voters petition for the removal of an elected official, are also included.
List of special elections
The dates listed indicate the time of the final election, either a runoff election or the open primary round if no second round was held.| District | Date | Predecessor | Winner |
| 33 | October 3, 1961 | James McBride | Robert Lagomarsino |
| 31 | February 13, 1962 | John Hollister | Alvin Weingand |
| 5 | March 16, 1965 | Edwin Regan | Fred Marler |
| 9 | August 15, 1967 | Gene McAteer | Milton Marks |
| 7 | March 25, 1969 | George Miller | John Nejedly |
| 34 | August 18, 1970 | John Schmitz | Dennis Carpenter |
| 27 | July 20, 1971 | George Danielson | David Roberti |
| 36 | June 6, 1972 | Gordon Cologne | W. Craig Biddle |
| 22 | February 27, 1973 | Tom Carrell | Alan Robbins |
| 38 | March 6, 1973 | Clair Burgener | John Stull |
| 20 | January 15, 1974 | William Coombs | Ruben Ayala |
| 24 | July 2, 1974 | Robert Lagomarsino | Omer Rains |
| 29 | April 1, 1975 | Mervyn Dymally | Bill Greene |
| 6 | June 8, 1976 | George Moscone | John Foran |
| 22 | March 8, 1977 | Anthony Beilenson | Alan Sieroty |
| 31 | April 17, 1979 | George Deukmejian | Ollie Speraw |
| 14 | June 9, 1979 | George Zenovich | Kenneth Maddy |
| 12 | June 5, 1980 | Jerry Smith | Dan O'Keefe |
| 35 | April 13, 1982 | John Briggs | John Seymour |
| 33 | May 12, 1987 | Paul Carpenter | Cecil Green |
| 39 | December 5, 1989 | Larry Stirling | Lucy Killea |
| 31 | April 10, 1990 | Bill Campbell | Frank Hill |
| 26 | April 10, 1990 | Joseph Montoya | Charles Calderon |
| 5 | January 8, 1991 | John Garamendi | Patrick Johnston |
| 1 | May 14, 1991 | John Doolittle | Tim Leslie |
| 35 | May 14, 1991 | John Seymour | John Lewis |
| 20 | June 2, 1992 | Alan Robbins | David Roberti |
| 32 | March 2, 1993 | Ed Royce | Rob Hurtt |
| 2 | April 27, 1993 | Barry Keene | Mike Thompson |
| 16 | April 27, 1993 | Don Rogers | Phil Wyman |
| 4 | November 2, 1993 | Mike Thompson | Maurice Johannessen |
| 11 | November 2, 1993 | Becky Morgan | Tom Campbell |
| 40 | December 28, 1993 | Wadie Deddeh | Steve Peace |
| 29 | November 8, 1994 | Frank Hill | Dick Mountjoy |
| 35 | May 9, 1995 | Marian Bergeson | Ross Johnson |
| 11 | March 26, 1996 | Tom Campbell | Byron Sher |
| 9 | September 1, 1998 | Barbara Lee | Don Perata |
| 32 | March 7, 2000 | Joe Baca | Nell Soto |
| 24 | March 6, 2001 | Hilda Solis | Gloria Romero |
| 35 | June 6, 2006 | John Campbell | Tom Harman |
| 26 | May 19, 2009 | Mark Ridley-Thomas | Curren Price |
| 37 | June 8, 2010 | John Benoit | Bill Emmerson |
| 15 | August 17, 2010 | Abel Maldonado | Sam Blakeslee |
| 1 | January 4, 2011 | Dave Cox | Ted Gaines |
| 17 | February 15, 2011 | George Runner | Sharon Runner |
| 28 | February 15, 2011 | Jenny Oropeza | Ted Lieu |
| 4 | January 8, 2013 | Doug LaMalfa | Jim Nielsen |
| 40 | March 2, 2013 | Juan Vargas | Ben Hueso |
| 32 | May 14, 2013 | Gloria Negrete McLeod | Norma Torres |
| 16 | July 23, 2013 | Michael Rubio | Andy Vidak |
| 26 | September 17, 2013 | Curren Price | Holly Mitchell |
| 23 | March 25, 2014 | Bill Emmerson | Mike Morrell |
| 35 | December 9, 2014 | Rod Wright | Isadore Hall, III |
| 21 | March 17, 2015 | Steve Knight | Sharon Runner |
| 37 | March 17, 2015 | Mimi Walters | John Moorlach |
| 7 | May 19, 2015 | Mark DeSaulnier | Steve Glazer |
| 32 | August 7, 2018 | Tony Mendoza | Vanessa Delgado |
| 1 | June 4, 2019 | Ted Gaines | Brian Dahle |
| 33 | June 4, 2019 | Ricardo Lara | Lena Gonzalez |
List of recall elections
When applicable, the candidate who succeeded the recalled state senator is listed. If the recall election was not successful the winner is listed as "none".| District | Date | Recall target | Replacement |
| 20 | April 12, 1994 | David Roberti | Not applicable, recall failed |
| 12 | June 3, 2008 | Jeff Denham | Not applicable, recall failed |
| 29 | June 5, 2018 | Josh Newman | Ling Ling Chang |