| Country: | Osun |
| Party1: | All Progressives Congress |
| Party2: | People's Democratic Party (Nigeria) |
| Previous Election: | 2014 Osun State gubernatorial election |
| Next Election: | 2022 Osun State gubernatorial election |
| Nominee1: | Gboyega Oyetola |
| Nominee2: | Ademola Adeleke |
| Election Date: | 22 September 2018 (first round) 27 September 2018 (rerun) |
| Popular Vote1: | 255,505 |
| Popular Vote2: | 255,023 |
| Ongoing: | no |
| Previous Year: | 2014 |
| Next Year: | 2022 |
| Type: | presidential |
| Governor | |
| Before Election: | Rauf Aregbesola |
| After Election: | Gboyega Oyetola |
| Before Party: | All Progressives Congress |
| After Party: | All Progressives Congress |
| Nominee3: | Iyiola Omisore |
| Party3: | Social Democratic Party (Nigeria) |
| Popular Vote3: | 128,053 |
| Percentage1: | 36.71% |
| Percentage2: | 36.64% |
| Percentage3: | 18.40% |
| Image3: | File:Iyiola-Omisore.png |
| Candidate4: | Moshood Adeoti |
| Party4: | Action Democratic Party (Nigeria) |
| Popular Vote4: | 49,745 |
| Percentage4: | 7.15% |
The Osun State gubernatorial election took place on 22 September 2018. The election was held alone where national and state level elections were to be held by 2019. Two-term incumbent Governor Rauf Aregbesola of the All Progressives Congress was in-eligible to run for re-election. Ademola Adeleke of the People's Democratic Party won the initial election as announced by INEC.[1] but was defeated in a rerun on 27 September by Gboyega Oyetola.[2]
Rauf Aregbesola previously served as a commissioner in Lagos State under Bola Tinubu's administration prior to becoming governor.
The rerun on 27 September was called after the first round was declared inconclusive, on account of Ademola's margin of victory being smaller than the number of cancelled votes in seven polling units[3]