The 2020 elections for the Illinois Senate took place on November 3, 2020 to elect senators from 22 of the state's 59 Senate districts to serve in the 102nd General Assembly, with seats apportioned among the states based on the 2010 United States Census. Under the Illinois Constitution of 1970, senators are divided into three groups, each group having a two-year term at a different part of the decade between censuses, with the rest of the decade being taken up by two four-year terms. The Democratic Party has held a majority in the Senate since 2003. The inauguration of the 102nd General Assembly occurred on Wednesday January 13, 2021.