2018 Illinois gubernatorial election

The 2018 Illinois gubernatorial election took place on November 6, 2018, to elect the governor of Illinois. Republican Governor Bruce Rauner ran for reelection to a second term in office, but was defeated by Democratic nominee JB Pritzker. This is the most recent Illinois gubernatorial contest in which an incumbent was defeated and the last time the governorship of Illinois changed partisan control.

Rauner oversaw a historic budget crisis as governor that severely affected his popularity. His approval rating declined to just 36% in 2017, and he was widely viewed as the most vulnerable incumbent governor in the country. Rauner struggled to galvanize conservatives after making several policy concessions to Democrats and was nearly ousted in the Republican primary by state senator Jeanne Ives. By October 2018, The Cook Political Report assessed that "there is no path to victory for Rauner."

Pritzker ultimately defeated Rauner by nearly 16 points, the largest gubernatorial victory in Illinois since Jim Edgar's 1994 reelection. Rauner's loss was the widest margin of defeat for any incumbent governor since Ernie Fletcher of Kentucky was ousted in 2007. This was one of seven governorships Democrats flipped during the 2018 cycle. Rauner's 38.8% of the vote was the worst performance for an incumbent Illinois governor since 1912; he also received the lowest percentage of the vote for a Republican since 1912. With Pritzker winning by a margin of 15.7%, this was the biggest gubernatorial margin of victory for a Democrat since 1932. He was the first Democrat to carry DuPage County since 1932, Kane and Kendall counties since 1852, and DeKalb County since 1972.