Michael J. Madigan (born April 19, 1942) is the Speaker of the Illinois House of Representatives and Chairman of the Democratic Party of Illinois. A Democrat, he has held the position of Speaker of the House for all but two years since 1983—those two years being a brief interregnum of Republican majority. He has been a member of the Illinois House since 1971, and currently represents the 22nd district.

Madigan was born in Chicago and has lived there most of his life. He attended St. Ignatius College Prep on the west side of Chicago. He attended college at the University of Notre Dame and graduated from the Loyola University Chicago School of Law. Madigan represents the 22nd Representative District on Chicago's southwest side. He has also served for many years as Democratic Committeeman of the 13th ward. His is generally considered one of the more effective ward organizations at a time when the vote-getting power of such groups has declined notably.

He has been Speaker of the Illinois House since 1982, with the exception of 1995–1996 when Republicans took control of the chamber. Madigan engineered a Democratic comeback and regained his majority at the elections of November 1996, which he continues to defend today. He has feuded with other Democratic leaders since 2002 – when Democrats took control of all branches of the state government – most notably Governor Rod Blagojevich and Senate President Emil Jones.