| Election Name: | 1856 Illinois gubernatorial election |
| Country: | Illinois |
| Type: | presidential |
| Ongoing: | Yes |
| Previous Election: | 1852 Illinois gubernatorial election |
| Previous Year: | 1852 |
| Next Election: | 1860 Illinois gubernatorial election |
| Next Year: | 1860 |
| Election Date: | November 4, 1856 |
| Nominee1: | William Henry Bissell |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 111,466 |
| Percentage1: | 46.97% |
| Nominee2: | William Alexander Richardson |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 106,769 |
| Percentage2: | 44.99% |
| Nominee3: | Buckner S. Morris |
| Party3: | Know Nothing |
| Popular Vote3: | 19,088 |
| Percentage3: | 8.04% |
| Map Size: | 300px |
| Governor | |
| Before Election: | Joel Aldrich Matteson |
| Before Party: | Democratic Party (United States) |
| After Election: | William Henry Bissell |
| After Party: | Republican Party (United States) |
The 1856 Illinois gubernatorial election was the eleventh election for this office. Democratic governor Joel Aldrich Matteson did not seek re-election. Former Democratic Congressman William Henry Bissell was nominated by the newly formed Republican Party at the Bloomington Convention. Former Whig Mayor of Chicago Buckner S. Morris was nominated on the Know-Nothing Party ticket.
The Democratic campaign focused upon Bissell's involvement in a duel with future Confederate President Jefferson Davis, legally disqualifying him from holding state office, while the Republican campaign emphasized the Kansas-Nebraska Act. Despite Bissell's victory, Republican presidential nominee John C. Fremont would fail to carry the state in the concurrent presidential election. This was the first election of a Republican governor in Illinois history, as well as the first election of a Catholic.
At this time in Illinois history the Lieutenant Governor was elected on a separate ballot from the governor. This would remain the case until the adoption of the 1970 constitution.