Judy Baar Topinka was an American politician and member of the Republican Party from the U.S. State of Illinois.

The Illinois Republican Party is the affiliate of the Republican Party in the U.S. state of Illinois founded on May 29, 1856. It is run by the Illinois Republican State Central Committee, which consists of 18 members, one representing each of the state's congressional districts. Once the dominant party in Illinois, the state GOP has become a minority party within the last few decades, holding little power in the state. The current chairman is Don Tracy, who has served since 2021.