The aim of the research was to assess how the selected factors could influence the performance of the best horses in dressage, jumping and eventing competitions. The research was based on the Studbook Rankings published by the World Breeding Federation for Sport Horses from 2019 to 2024. Our analysis shows a statistically significant effect of each of the observed factors in at least one discipline. The leading factor in all disciplines was studbook affiliation. The Belgian warmblood, German Sport Horse, Hanoverian, Royal Dutch Sport Horse, Oldenburg and Westphalian studbooks are represented among the significantly best studbooks in all three disciplines. Geldings were statistically highly demonstrably the best in jumping. In eventing, both geldings and stallions were highly significantly better than mares. Significantly, the highest performance was achieved by 11-year-old horses in jumping and by 15-year-old horses in eventing. We have demonstrated a statistical effect of the proportion of thoroughbred genes on performance in dressage. Statistically better performance in a selected elite population of dressage horses was achieved by horses with 20% to 50% thoroughbred genes. Our results confirm the necessity of selecting sport horses based on specialized performance tests and the need for different breeding programs for success in individual equestrian sports.