The 5th Illinois General Assembly, consisting of the Illinois Senate and the Illinois House of Representatives, met from December 4, 1826, to February 19, 1827, at The Vandalia State House. The apportionment of seats in the House of Representatives was based on the provisions of the . Political parties were not established in Illinois at the time.
The 5th General Assembly was preceded by the 4th Illinois General Assembly, and was succeeded by the 6th Illinois General Assembly.
Senators and Representatives were both allotted to counties roughly by population and elected at-large within their districts. Bond and Montgomery counties shared a single senator.