| Election Name: | 1873 United States Senate special election in California |
| Type: | presidential |
| Ongoing: | no |
| Flag Image: | First Bear Flag of California (1846).svgborder |
| Previous Election: | 1867 United States Senate election in California |
| Previous Year: | 1867 |
| Next Election: | 1873 United States Senate election in California |
| Next Year: | 1873 |
| Election Date: | December 23, 1873 |
| Votes For Election: | Majority vote of both houses needed to win |
| 1Blank: | Joint session |
| 2Blank: | Percentage |
| Image1: | John S. Hager 3x4.jpg |
| Nominee1: | John S. Hager |
| Party1: | Democratic Party (United States) |
| 1Data1: | 55 |
| 2Data1: | 53.92% |
| Nominee2: | Thomas H. Laine |
| Party2: | Independent |
| 1Data2: | 20 |
| 2Data2: | 19.61% |
| Image4: | Oscar L. Shafter 3x4.jpg |
| Nominee4: | Oscar L. Shafter |
| Party4: | Republican Party (United States) |
| 1Data4: | 13 |
| 2Data4: | 12.75% |
| Image5: | Hon. Cornelius Cole, Calif Panel 1 3x4.jpg |
| Nominee5: | Cornelius Cole |
| Party5: | Republican Party (United States) |
| 1Data5: | 8 |
| 2Data5: | 7.84% |
| Senator | |
| Before Election: | Eugene Casserly |
| Before Party: | Democratic Party (United States) |
| After Election: | John S. Hager |
| After Party: | Democratic Party (United States) |
The 1873 United States Senate special election in California was held on December 23, 1873, by the California State Legislature to elect a U.S. Senator (Class 1) to represent the State of California in the United States Senate. In a special joint session, Democratic State Senator John S. Hager was elected over People's Independent State Senator Thomas H. Laine, former Republican State Supreme Court Justice Oscar L. Shafter, and former Republican U.S. Senator Cornelius Cole.[1]