The Supreme Court of Illinois is the state supreme court, the highest court of the judiciary of Illinois. The court's authority is granted in Article VI of the current Illinois Constitution, which provides for seven justices elected from the five appellate judicial districts of the state: three justices from the First District (Cook County) and one from each of the other four districts. Absent mid-term vacancy, each justice is elected for a term of ten years, which may be renewed and the chief justice is elected by the court from its members for a three-year term.

The court has limited original jurisdiction and has final appellate jurisdiction in Illinois state law matters. If its decision also involves a federal question, it may be further appealed to the United States Supreme Court. It has jurisdiction in cases where the constitutionality of laws has been called into question, and discretionary jurisdiction from the Illinois Appellate Court. Until 2011, when Illinois abolished the death penalty, it had mandatory jurisdiction in capital cases. Along with the state legislature, the court promulgates rules for all state courts. Also, its members have the authority to elevate trial judges to the appellate court on a temporary basis. The court administers professional discipline through the Attorney Registration and Disciplinary Committee and it governs initial licensing through the Illinois Board of Admissions to the Bar.

For publication of its decisions and rulings, the official law report of the Illinois Supreme Court is Illinois Reports.

The Illinois Supreme Court is separated into 5 districts, with one Justice elected from each except the 1st, which elects three Justices. The districts are separated along county lines.

These districts were first established in 1963 and had not been updated in nearly sixty years, despite the Illinois Constitution's requirement that the four districts outside the 1st District (Cook County) have "substantially equal population". As of 2018 Census estimates, the populations of the old districts before the 2021 redistricting were: 1st District: 5,194,000; 2nd District: 3,189,000; 3rd District: 1,805,000; 4th District 1,320,000; 5th District: 1,321,000. In comparison, the 2020 Census reports the populations of the current districts as: 1st District: 5,275,541; 2nd District: 1,773,382; 3rd District: 1,959,246; 4th District 2,086,825; 5th District: 1,717,514. The state legislature redrew districts in 2021 to take effect in the 2022 elections, Illinois Governor J. B. Pritzker signed these changes into law.

Below are the counties per district based on the 2021 redistricting. Only the first district has remained entirely the same.

• Cook

Justices are required to be U.S. citizens, members of the state bar, and resident in the district from which they are elected or appointed. Justices run in a general election for a 10-year term. At the end of the initial term, they may run in a non-partisan retention election where they must receive 60% of the vote to be retained for continuing terms of ten years. When a vacancy occurs mid-term, the Supreme Court itself appoints a new justice. The appointed justice must run in the next partisan election (including primaries) that is more than 60 days from their appointment for a 10-year term to hold the seat. The court elects the chief justice from among its members for a three-year term.

While the justices of many states' supreme courts are expected to relocate to the state capital for the duration of their terms of office, the justices of the Illinois Supreme Court continue to reside in their home constituencies and have chambers in their respective appellate districts (for example, the three First District justices are chambered in the Michael Bilandic Building in Chicago). The justices travel to Springfield to hear oral arguments and deliberate. Accordingly, the Illinois Supreme courthouse building includes apartments for the justices' use while in Springfield.

District	Justice	Born	Joined	Chief Justice	Term ends	Party affiliation	Law school
1st	Mary Jane Theis, Chief Justice	(1949-02-27) February 27, 1949 (age 75)	October 26, 2010	2022–present	2032	Democratic	USF
	P. Scott Neville Jr.	1948 or 1949 (age 75–76)	June 15, 2018	–	2030	Democratic	WashU
	Joy Cunningham	1951 (age 72–73)	December 1, 2022	–	2034	Democratic	UIC
2nd	Elizabeth Rochford	1960 or 1961 (age 63–64)	December 5, 2022	–	2032	Democratic	Loyola
3rd	Mary Kay O'Brien	(1965-06-04) June 4, 1965 (age 59)	December 5, 2022	–	2032	Democratic	Illinois
4th	Lisa Holder White	1968 (age 55–56)	July 8, 2022	–	2034	Republican	Illinois
5th	David K. Overstreet	(1966-01-14) January 14, 1966 (age 58)	December 7, 2020	–	2030	Republican	Tennessee

This list is incomplete; you can help by adding missing items. (October 2008)

• Thomas R. Fitzgerald (2000–2010)
• Philip J. Rarick (2002–2004)
• Robert R. Thomas (2000–2020)
• Thomas L. Kilbride (2000–2020)
• Rita Garman (2001–2022)
• Anne M. Burke (2006–2022)
• Michael J. Burke (2020–2022)
• Robert L. Carter (2020–2022)
• Lloyd A. Karmeier (2004-2020)

• Judiciary of Illinois

• List of Supreme Court Justices from Supreme Court's website
• Scammon, J. Young (1841). Illinois Reports v. 1 (2 ed.). Chicago: Gale & Burley.
• Gilman, Charles; Russell H. Curtis (1886). Illinois Reports v. 10. Chicago: Callaghan & Co.
• Peck, E. (1856). Illinois Reports v. 16. Chicago: D. B. Cooke & Co.
• Peck, E. (1869). Illinois Reports v. 16 (2 ed.). St. Louis: W. J. Gilbert.
• Peck, E. (1858). Illinois Reports v. 19. Chicago: D. B. Cooke & Co.
• Ewell, Marshall D. Illinois Reports v. 33.
• Freeman, Norman L. (1866). Illinois Reports v. 44. Callaghan & Co.

• Illinois Supreme Court website
• A Chronicle of the Illinois Supreme Court
• Illinois State Judiciary
• Chief Justices of the Illinois Supreme Court
• Illinois Supreme Court Historic Preservation Commission