The 1965–66 season was the 63rd season of competitive football in Belgium. RSC Anderlechtois won their 12th Division I title and became the club with the most championship wins in Belgium. They also entered the 1965–66 European Champion Clubs' Cup as Belgian title holder. As RSC Anderlechtois was also the Cup holder, the losing finalist Standard Liège entered the 1965–66 European Cup Winners' Cup. RFC Liégeois, R Daring Club de Bruxelles and R Antwerp FC all played the 1965–66 Inter-Cities Fairs Cup. Standard Liège won the Belgian Cup final against rivals RSC Anderlechtois (1-0). The Belgium national football team ended their 1966 FIFA World Cup qualification campaign with pain, and a defeat to Bulgaria in a play-off game for the World Cup finals qualification (2-1 in Florence, Italy).