Karel Geraerts (Dutch pronunciation: [ˈkaːrəl ˈɣeːraːrts]; born 5 January 1982) is a Belgian former footballer and head coach of Schalke 04.

Geraerts played for Club Brugge from 1998 to December 2003. In 2004 Club Brugge lent him to Lokeren where he scored his first goal in the Jupiler League. In the summer of 2004 he moved to Standard Liège. In June 2007, he went back to Bruges. As a youngster, the midfielder played with C.S. Mechelen-aan-de-Maas and Racing Genk (from 1996 to 1998) before he moved to the youth team of Club Brugge. After the 2010–11 season, Geraerts was no longer part of the plans at Club Brugge and was told he could look for a new club, which resulted in him signing with newly promoted side OH Leuven on the last day of the transfer window.^[1] Geraerts' contract ended in 2014 and with Oud-Heverlee Leuven just being relegated, it was not renewed. This allowed him to move as a free agent player to Charleroi. He last played for Charleroi in 2016 and after being without a club for half a year has announced his retirement in January 2017.^[2]

In 2005, Geraerts debuted for the Belgium national football team. In his first match in the starting line-up, on 12 October in and against Lithuania in a World Cup qualifier, he scored the opening goal.

After managing Union SG for a year, he moved to Schalke 04 in 2023.^[3]