CHIO Aachen has been an international horse tournament since 1924, occurring in Aachen, Germany. According to the rules of the International Federation for Equestrian Sports (FEI), each country may only stage one CHIO. Therefore CHIO Aachen is the only event of its kind in Germany. Its organizer is the Aachen-Laurensberger Rennverein society, which was founded in 1898. Its venue is the Reitstadion in the Soers. In addition to the title and following the nomenclature for the tournament, the CHIO has been held under the self-chosen name "World Equestrian Festival" (Weltfest des Pferdesports) since 1992.
CHIO Aachen consists of the disciplines of show jumping, dressage, racing, and the newly introduced disciplines of 2007: eventing and vaulting). There is always a victor in the single and team classes.