Koninklijke Racing Club Genk (Dutch pronunciation: [ˈkoːnɪŋkləkə ˈreːsɪŋ ˌklʏp ˈxɛŋk]), commonly known as KRC Genk or Racing Genk, is a Belgian professional football club based in the city of Genk in Belgian Limburg. Racing Genk plays in the Belgian Pro League and have won four championship titles; in 1998–99, in 2001–02, in 2010–11 and in 2018–19. They have also won five Belgian Cups, most recently in 2020–21. They qualified for the UEFA Champions League group stage in the 2002–03, 2011–12 and 2019–20.

The club formed in 1988 by the merger of Waterschei Thor with KFC Winterslag, from which it took over the matricule number. It has been one of the most successful clubs in Belgium since the late 1990s and so they regularly qualify for European competitions. The club has been playing in the first division since the 1996–97 season. They play their home matches in the Cegeka Arena. Their main outfit is blue and white.

The club FC Winterslag was founded in 1923 and that gave it the matricule number 322. On its 35th anniversary the club added the Royal prefix Koninklijke to their name to become KFC Winterslag. In 1972–73 Winterslag reached the second division and they eventually qualified for the 1974–75 Belgian First Division after finishing second in the second division final round. They had taken advantage of the increase in the number of first division clubs (from 16 to 20). The club ended the season in last place but won the second division right after.

KFC Winterslag reached the 5th place in 1981 which allowed them to play UEFA Cup matches, where it defeated Bryne FK from Norway and English Premier league giant Arsenal. In the next round it was knocked out by Dundee United from Scotland. Two seasons later it was relegated to the second stage after a disappointing last place. That season Standard Liège won the championship on bribery in a match against the club of Waterschei Thor that would eventually merge with the matricule number 322. Following a spell of four seasons in the second division, Winterslag found its place again in the first division by winning the 1987 final round, one point ahead of Tongeren. It finished 15th on 18 but at the end of the season, the club merged with the neighbour club of Waterschei Thor which was playing in the second division since its relegation in 1986.

K Waterschei SV Thor was created in 1919 as Waterschei's Sport Vereeniging Thor with Thor being the acronym of Tot Herstel Onzer Rechten (English: To recover our rights). It received matricule number n°533. The club enjoyed a spell in the first division in the late 1950s to the early 1960s and again from 1978 to 1986.

During the 1982–83 season, the match between Standard Liège and Waterschei had been fixed [fr] and Standard eventually won the championship. Waterschei won the Belgian Cup twice (1980 and 1982). The latter victory led to them reaching the semi-finals of the European Cup Winners Cup in the 1982–83 season. After defeating PSG in the quarter-finals, Waterschei lost the first leg of the semi-final 5–1 at Pittodrie Stadium, home of the eventual winners, Aberdeen A 1–0 victory in Waterschei, courtesy of Eddy Voordeckers, could not reverse the position.

After two seasons in the second division, K. Waterschei SV Thor Genk merged with KFC Winterslag in 1988 to form the current KRC Genk.

1990s and 2000s