A general election was held in the U.S. state of Illinois on November 6, 2018. The elections for Illinois's 18 congressional districts, governor, statewide constitutional officers, Illinois Senate, and Illinois House were held on this date.

Primaries were held March 20, 2018.

The Democratic Party made gains, including picking up the state's governorship and flipping two of its U.S. House seats. After the election, all executive offices and control of the Illinois General Assembly was held by the Democratic Party. Conversely the Republican Party experienced what was regarded to be their worst defeat in the state since at least 2006.

2018 was a midterm election year in the United States.

For the primary election, turnout was 26.48%, with 2,103,634 votes cast.

Turnout by county

For the general election, turnout was 57.23%, with 4,635,541 votes cast. The Illinois State Board of Elections reported that this general election turnout rate was the third-highest for a midterm election over the past forty years. The Illinois State Board of Elections also reported that the total number of votes cast set a record high. Voter registration, at 8.1 million, also sat at a record high.

Turnout was considered high in the United States during the 2018 midterm elections, with it being the highest national midterm turnout since 1914.