| Election Name: | 2018 California Superintendent of Public Instruction election |
| Country: | California |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 2014 California Superintendent of Public Instruction election |
| Previous Year: | 2014 |
| Next Election: | 2022 California Superintendent of Public Instruction election |
| Next Year: | 2022 |
| Election Date: | June 5, 2018 (first round) November 6, 2018 (runoff) |
| 1Blank: | First round |
| 2Blank: | Runoff |
| Image1: | File:Assemblymember Tony Thurmond (cropped).jpg |
| Candidate1: | Tony Thurmond |
| Color1: | c0c0c0 |
| 1Data1: | 2,136,919 35.6% |
| 2Data1: | 5,385,912 50.9% |
| Candidate2: | Marshall Tuck |
| Color2: | c0c0c0 |
| 1Data2: | 2,223,784 37.0% |
| 2Data2: | 5,198,738 49.1% |
| Candidate4: | Lily Ploski |
| Color4: | c0c0c0 |
| 1Data4: | 984,932 16.4% |
| 2Data4: | Eliminated |
| Candidate5: | Steven Ireland |
| Color5: | c0c0c0 |
| 1Data5: | 658,786 11.0% |
| 2Data5: | Eliminated |
| SPI | |
| Map Size: | 300px |
| Before Election: | Tom Torlakson |
| After Election: | Tony Thurmond |
The 2018 California Superintendent of Public Instruction primary election was held on June 5, 2018, to elect the Superintendent of Public Instruction of California. Unlike most other elections in California, the superintendent is not elected under the state's "top-two primary". Instead, the officially nonpartisan position is elected via a general election, with a runoff held on November 6, 2018, because no candidate received a majority of the vote.
The previous incumbent, Superintendent Tom Torlakson, was term-limited, so could not seek a third term. As no candidate received a majority in the general election, a runoff was held between two Democrats: Marshall Tuck and Tony Thurmond. Thurmond narrowly defeated Tuck.
| Poll source | Date(s) administered | Sample size | Margin of error | Tony Thurmond | Marshall Tuck | Undecided | |||
|---|---|---|---|---|---|---|---|---|---|
| UC Berkeley | October 19–26, 2018 | 1,339 | ± 4.0% | 36% | align=center | 48% | 16% | ||
| Thomas Partners Strategies | October 18–20, 2018 | 1,068 | ± 3.5% | 35% | align=center | 37% | 28% | ||
| Thomas Partners Strategies | October 5–7, 2018 | 1,068 | ± 3.5% | 28% | align=center | 30% | align=center | 41% | |
| Thomas Partners Strategies | September 28–30, 2018 | 1,068 | ± 3.5% | 17% | align=center | 29% | align=center | 54% |